Gene Summary

Gene:PDGFRA; platelet-derived growth factor receptor, alpha polypeptide
Summary:This gene encodes a cell surface tyrosine kinase receptor for members of the platelet-derived growth factor family. These growth factors are mitogens for cells of mesenchymal origin. The identity of the growth factor bound to a receptor monomer determines whether the functional receptor is a homodimer or a heterodimer, composed of both platelet-derived growth factor receptor alpha and beta polypeptides. Studies suggest that this gene plays a role in organ development, wound healing, and tumor progression. Mutations in this gene have been associated with idiopathic hypereosinophilic syndrome, somatic and familial gastrointestinal stromal tumors, and a variety of other cancers. [provided by RefSeq, Mar 2012]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:platelet-derived growth factor receptor alpha
Source:NCBIAccessed: 11 August, 2015


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 11 August 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 11 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (11)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Gastrointestinal CancersPDGFRA and Gastrointestinal Cancers View Publications377
Gastrointestinal Stromal TumorsPDGFRA and Gastrointestinal Stromal Tumors View Publications342
LeukaemiaFIP1L1-PDGFRA fusion in Leukemia
Fusions of the FIP1L1 and PDGFRA genes are reported in acute myeloid leukemia, T-cell lymphoblastic lymphoma, chronic eosinophilic leukemia - all with eosinophilia (Bain, 2010). Cools et al (2003) reported that many examples of what had previously been categorized as idiopathic hypereosinophilic syndrome were actually chronic eosinophilic leukemia - and that this condition with the FIP1L1-PDGFRA fusion is sensitive to treatments with tyrosine kinase inhibitors such as imatinib. Most FIP1L1-PDGFRA fusions are caused by a cryptic deletion: del(4)(q12), but occasionally by other rearrangements such as translocations t(1;4)(q44;q12)6 and t(4;10)(q12;p11).
View Publications66
LeukaemiaPDGFRA and Leukaemia View Publications52
Skin CancerPDGFRA and Skin Cancer View Publications8
Thyroid CancerPDGFRA and Thyroid Cancer View Publications2
-FIP1L1-PDGFRA Fusions in Myeloid Sarcoma
Myeloid sarcoma (aka granulocytic sarcoma) is a rare extramedullary tumor of immature granulocytic cells, usually accompanied by or following acute myeloid leukemia (Yilmaz et al, 2013). The fusion if the FIP1L1-PDGFRA genes is reported in some meyloid sarcomas.
View Publications6
Cervical CancerPDGFRA and Cervical Cancer View Publications4
Stomach CancerPDGFRA and Stomach Cancer View Publications41
Testicular CancerPDGFRA and Testicular Cancer View Publications6

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: PDGFRA (cancer-related)

Cheng Y, Ma D, Zhang Y, et al.
Cervical squamous cancer mRNA profiles reveal the key genes of metastasis and invasion.
Eur J Gynaecol Oncol. 2015; 36(3):309-17 [PubMed] Related Publications
PURPOSE OF INVESTIGATION: To investigate mRNA expression profiles associated with cervical squamous carcinoma progression and to identify key genes involved in invasion and metastasis of cervical squamous cancer.
MATERIALS AND METHODS: The authors extracted the mRNA expression profile of eight normal cervical tissues by human whole genome microarray. The main functions of differentially expressed genes were identified by gene ontology (GO) analysis. Gene-networks were established based on bioinformatic approaches. Microarray data of the expressions level of key genes verified by qRT-PCR.
RESULTS: The authors identified 2036 differentially expressed genes between two groups including 1,282 down-regulated genes and 754 up-regulated genes (p < 0.05, FDR < 0.05). Gene-network revealed that PDGFRA, CAV1, and GJA-1 were critical for cervical cancer invasion and metastasis.
CONCLUSIONS: PDGFRA, CAV1, and GJA-1 were revealed as key node genes for cervical cancer invasion and metastasis. The results may provide new evidences and ideas for early diagnosis and prognosis assessment of cervical cancer.

Kumar A, Pathak P, Purkait S, et al.
Oncogenic KIAA1549-BRAF fusion with activation of the MAPK/ERK pathway in pediatric oligodendrogliomas.
Cancer Genet. 2015; 208(3):91-5 [PubMed] Related Publications
Pediatric oligodendrogliomas (pODGs) are rare central nervous system tumors, and comparatively little is known about their molecular pathogenesis. Co-deletion of 1p/19q; and IDH1, CIC, and FUBP1 mutations, which are molecular signatures of adult oligodendrogliomas, are extremely rare in pODGs. In this report, two pODGs, one each of grade II and grade III, were evaluated using clinical, radiological, histopathologic, and follow-up methods. IDH1, TP53, CIC, H3F3A, and BRAF-V600 E mutations were analyzed by Sanger sequencing and immunohistochemical methods, and 1p/19q co-deletion was analyzed by fluorescence in situ hybridization. PDGFRA amplification, BRAF gain, intragenic duplication of FGFR-TKD, and KIAA1549-BRAF fusion (validated by Sanger sequencing) were analyzed by real-time reverse transcription PCR. Notably, both cases showed the oncogenic KIAA1549_Ex15-BRAF_Ex9 fusion transcript. Further, immunohistochemical analysis showed activation of the MAPK/ERK pathway in both of these cases. However, neither 1p/19q co-deletion; IDH1, TP53, CIC, H3F3A, nor BRAF-V600 E mutation; PDGFRA amplification; BRAF gain; nor duplication of FGFR-TKD was identified. Overall, this study highlights that pODGs can harbor the KIAA1549-BRAF fusion with aberrant MAPK/ERK signaling, and there exists an option of targeting these pathways in such patients. These results indicate that pODGs with the KIAA1549-BRAF fusion may represent a subset of this rare tumor that shares molecular and genetic features of pilocytic astrocytomas. These findings will increase our understanding of pODGs and may have clinical implications.

Kikuchi A, Monga SP
PDGFRα in liver pathophysiology: emerging roles in development, regeneration, fibrosis, and cancer.
Gene Expr. 2015; 16(3):109-27 [PubMed] Free Access to Full Article Related Publications
Platelet-derived growth factor receptor α (PDGFRα) is an isoform of the PDGFR family of tyrosine kinase receptors involved in cell proliferation, survival, differentiation, and growth. In this review, we highlight the role of PDGFRα and the current evidence of its expression and activities in liver development, regeneration, and pathology-including fibrosis, cirrhosis, and liver cancer. Studies elucidating PDGFRα signaling in processes ranging from profibrotic signaling, angiogenesis, and oxidative stress to epithelial-to-mesenchymal transition point toward PDGFRα as a potential therapeutic target in various hepatic pathologies, including hepatic fibrosis and liver cancer. Furthermore, PDGFRα localization and modulation during liver development and regeneration may lend insight into its potential roles in various pathologic states. We will also briefly discuss some of the current targeted treatments for PDGFRα, including multi receptor tyrosine kinase inhibitors and PDGFRα-specific inhibitors.

Lopez-Chavez A, Thomas A, Rajan A, et al.
Molecular profiling and targeted therapy for advanced thoracic malignancies: a biomarker-derived, multiarm, multihistology phase II basket trial.
J Clin Oncol. 2015; 33(9):1000-7 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
PURPOSE: We conducted a basket clinical trial to assess the feasibility of such a design strategy and to independently evaluate the effects of multiple targeted agents against specific molecular aberrations in multiple histologic subtypes concurrently.
PATIENTS AND METHODS: We enrolled patients with advanced non-small-cell lung cancer (NSCLC), small-cell lung cancer, and thymic malignancies who underwent genomic characterization of oncogenic drivers. Patients were enrolled onto a not-otherwise-specified arm and treated with standard-of-care therapies or one of the following five biomarker-matched treatment groups: erlotinib for EGFR mutations; selumetinib for KRAS, NRAS, HRAS, or BRAF mutations; MK2206 for PIK3CA, AKT, or PTEN mutations; lapatinib for ERBB2 mutations or amplifications; and sunitinib for KIT or PDGFRA mutations or amplification.
RESULTS: Six hundred forty-seven patients were enrolled, and 88% had their tumors tested for at least one gene. EGFR mutation frequency was 22.1% in NSCLC, and erlotinib achieved a response rate of 60% (95% CI, 32.3% to 83.7%). KRAS mutation frequency was 24.9% in NSCLC, and selumetinib failed to achieve its primary end point, with a response rate of 11% (95% CI, 0% to 48%). Completion of accrual to all other arms was not feasible. In NSCLC, patients with EGFR mutations had the longest median survival (3.51 years; 95% CI, 2.89 to 5.5 years), followed by those with ALK rearrangements (2.94 years; 95% CI, 1.66 to 4.61 years), those with KRAS mutations (2.3 years; 95% CI, 2.3 to 2.17 years), those with other genetic abnormalities (2.17 years; 95% CI, 1.3 to 2.74 years), and those without an actionable mutation (1.85 years; 95% CI, 1.61 to 2.13 years).
CONCLUSION: This basket trial design was not feasible for many of the arms with rare mutations, but it allowed the study of the genetics of less common malignancies.

Joensuu H, Rutkowski P, Nishida T, et al.
KIT and PDGFRA mutations and the risk of GI stromal tumor recurrence.
J Clin Oncol. 2015; 33(6):634-42 [PubMed] Related Publications
PURPOSE: Mutated KIT and platelet-derived growth factor alpha gene (PDGFRA) drive GI stromal tumor (GIST) oncogenesis, but the clinical significance of their single mutations is known incompletely.
PATIENTS AND METHODS: We identified 11 population-based series of patients with GIST through a literature search and pooled individual data from 3,067 patients treated with macroscopically complete tumor excision. Mutation analysis was done from 1,505 tumors. We analyzed associations between KIT and PDGFRA mutations and recurrence-free survival (RFS) in the subsets in which patients were treated with surgery alone.
RESULTS: We identified 301 different single mutations in KIT and 33 in PDGFRA. Patients with PDGFRA mutations had more favorable RFS than those with KIT mutations (hazard ratio, 0.34; P = .004). Only one of the 35 GISTs with KIT exon 11 duplication mutations recurred. Patients with deletions of only one codon of KIT exon 11 had better RFS than those with another deletion type, and some KIT exon 11 substitution mutations (Trp557Arg, Val559Ala, and Leu576Pro) were also associated with favorable RFS. Patients with an identical mutation had greatly variable outcomes depending on the standard prognostic factors, notably, mitotic count. Commonly used risk stratification schemes tended to overestimate the risk for recurrence in subgroups with prognostically favorable mutations.
CONCLUSION: GISTs with an identical KIT or PDGFRA mutation may have widely varying risks for recurrence. Most of the patients with PDGFRA mutations and those with KIT exon 11 duplication mutation or deletion of one codon have favorable RFS with surgery alone and are usually not candidates for adjuvant therapy.

Wen YS, Cai L, Zhang XW, et al.
Concurrent oncogene mutation profile in Chinese patients with stage Ib lung adenocarcinoma.
Medicine (Baltimore). 2014; 93(29):e296 [PubMed] Related Publications
Molecular characteristics in lung cancer are associated with carcinogenesis, response to targeted therapies, and prognosis. With concurrent oncogene mutations being reported more often, the adjustment of treatment based on the driver gene mutations would improve therapy. We proposed to investigate the distribution of concurrent oncogene mutations in stage Ib lung adenocarcinoma in a Chinese population and find out the correlation between survival outcome and the most frequently mutated genes in EGFR and KRAS in Chinese population. Simultaneously, we tried to validate the Sequenom method by real time fluoresce qualification reverse transcription polymerase chain reaction (RT-PCR) in oncogene detection. One hundred fifty-six patients who underwent complete surgical resection in our hospital between 1999 and 2007 were retrospectively investigated. Using time-of-flight mass spectrometry, 238 mutation hotspots in 19 oncogenes were examined. Genetic mutations occurred in 86 of 156 patients (55.13%). EGFR was most frequently gene contained driver mutations, with a rate of 44.23%, followed by KRAS (8.33%), PIK3CA (3.84%), KIT (3.20%), BRAF (2.56%), AKT (1.28%), MET (0.64%), NRAS (0.64%), HRAS (0.64%), and ERBB2 (0.64%). No mutations were found in the RET, PDGFRA, FGFR1, FGFR3, FLT3, ABL, CDK, or JAK2 oncogenes. Thirteen patients (8.3%) were detected in multiple gene mutations. Six patients had PIK3CA mutations in addition to mutations in EGFR and KRAS. EGFR mutations can coexist with mutations in NRAS, KIT, ERBB2, and BRAF. Only one case was found to have a KRAS mutation coexisting with the EGFR T790M mutation. Otherwise, mutations in EGFR and KRAS seem to be mutually exclusive. There is no survival benefit in favor of EGFR/KRAS mutation. Several concomitant driver gene mutations were observed in our study. None of EFGR/KRAS mutation was demonstrated as a prognostic factor. Polygenic mutation testing by time-of-flight mass spectrometry was validated by RT-PCR, which can be an alternative option to test for multiple mutations and can be widely applied to clinical practice and help to guide treatment.

Funato K, Major T, Lewis PW, et al.
Use of human embryonic stem cells to model pediatric gliomas with H3.3K27M histone mutation.
Science. 2014; 346(6216):1529-33 [PubMed] Related Publications
Over 70% of diffuse intrinsic pediatric gliomas, an aggressive brainstem tumor, harbor heterozygous mutations that create a K27M amino acid substitution (methionine replaces lysine 27) in the tail of histone H3.3. The role of the H3.3K27M mutation in tumorigenesis is not fully understood. Here, we use a human embryonic stem cell system to model this tumor. We show that H3.3K27M expression synergizes with p53 loss and PDGFRA activation in neural progenitor cells derived from human embryonic stem cells, resulting in neoplastic transformation. Genome-wide analyses indicate a resetting of the transformed precursors to a developmentally more primitive stem cell state, with evidence of major modifications of histone marks at several master regulator genes. Drug screening assays identified a compound targeting the protein menin as an inhibitor of tumor cell growth in vitro and in mice.

Meng F, Speyer CL, Zhang B, et al.
PDGFRα and β play critical roles in mediating Foxq1-driven breast cancer stemness and chemoresistance.
Cancer Res. 2015; 75(3):584-93 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
Many epithelial-mesenchymal transition (EMT)-promoting transcription factors have been implicated in tumorigenesis and metastasis as well as chemoresistance of cancer. However, the underlying mechanisms mediating these processes are unclear. Here, we report that Foxq1, a forkhead box-containing transcription factor and EMT-inducing gene, promotes stemness traits and chemoresistance in mammary epithelial cells. Using an expression profiling assay, we identified Twist1, Zeb2, and PDGFRα and β as Foxq1 downstream targets. We further show that PDGFRα and β can be directly regulated by Foxq1 or indirectly regulated through the Foxq1/Twist1 axis. Knockdown of both PDGFRα and β results in more significant effects on reversing Foxq1-promoted oncogenesis in vitro and in vivo than knockdown of either PDGFRα or β alone. In addition, PDGFRβ is a more potent mediator of Foxq1-promoted stemness traits than PDGFRα. Finally, pharmacologic inhibition or gene silencing of PDGFRs sensitizes mammary epithelial cells to chemotherapeutic agents in vitro and in vivo. These findings collectively implicate PDGFRs as critical mediators of breast cancer oncogenesis and chemoresistance driven by Foxq1, with potential implications for developing novel therapeutic combinations to treat breast cancer.

Appin CL, Brat DJ
Molecular pathways in gliomagenesis and their relevance to neuropathologic diagnosis.
Adv Anat Pathol. 2015; 22(1):50-8 [PubMed] Related Publications
Gliomas are a large and diverse group of primary brain tumors that include those that are diffusely infiltrative and others that are well-circumscribed and low grade. Diffuse gliomas are currently classified by the World Health Organization as astrocytomas, oligodendrogliomas, or oligoastrocytomas and range in grade from II to IV. Glioblastoma (GBM), World Health Organization grade IV, is the highest grade and most common form of astrocytoma. In the past, the diagnosis of gliomas was almost exclusively based on histopathologic features. More recently, improved understanding of molecular genetic underpinnings has led to ancillary molecular studies becoming standard for classification, prognostication, and predicting therapy response. Isocitrate dehydrogenase (IDH) mutations are frequent in grade II and III infiltrating gliomas and secondary GBMs. Infiltrating astrocytomas and secondary GBMs are characterized by IDH, TP53, and ATRX mutations, whereas oligodendrogliomas demonstrate 1p/19q codeletion and mutations in IDH, CIC, FUBP1, and the telomerase reverse transcriptase (TERT) promoter. Primary GBMs typically lack IDH mutations and are instead characterized by EGFR, PTEN, TP53, PDGFRA, NF1, and CDKN2A/B alterations and TERT promoter mutations. Pediatric GBMs differ from those in adults and frequently have mutations in H3F3A, ATRX, and DAXX, but not IDH. In contrast, circumscribed, low-grade gliomas of childhood, such as pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and ganglioglioma, often harbor mutations or activating gene rearrangements in BRAF. Neuropathologic assessment of gliomas increasingly relies on ancillary testing of molecular alterations for proper classification and patient management.

Bordi P, Tiseo M, Barbieri F, et al.
Gene mutations in small-cell lung cancer (SCLC): results of a panel of 6 genes in a cohort of Italian patients.
Lung Cancer. 2014; 86(3):324-8 [PubMed] Related Publications
BACKGROUND: No target therapies are presently available in the treatment of small-cell lung cancer (SCLC). We investigated the presence of potentially drugable mutations in the EGFR, c-MET, BRAF, KRAS, PDGFRa and c-KIT genes in a retrospective series of SCLC from 2 Italian Institutions. Correlations with immunohistochemical, clinical and outcome features were evaluated.
MATERIALS AND METHODS: Genes were studied by direct sequencing of DNA extracted from formalin-fixed paraffin-embedded tissues. Immunohistochemical expression of TTF-1, p63, chromogranin, synaptophysin, CD56 and bcl-2 was assessed.
RESULTS: Samples from 113 SCLC patients were analyzed. All cases were wild-type for BRAF, KRAS, PDGFRa and c-KIT (data available for 82 patients). Two (1.8%) patients were EGFR-mutated (exon 19 delE746-A750 and exon 21 L858R); both were females, non-smoker and had limited disease. Overall survival of EGFR-mutated patients was 21 months as compared to 11 months in wild-type. Five (4.4%) patients were c-MET-mutated (4 on exon 14: 2 R988C, 1 D990N, 1 D102Y; 1 on exon 17 R1166Q); all were smokers, 3 were males and 4 had extensive disease. Their OS was comparable to wild-type cases (12 vs. 11 months). EGFR and c-MET mutations were mutually exclusive. Gene mutations did not correlate with immunophenotype.
CONCLUSIONS: Targetable mutations are uncommon in SCLC. EGFR-mutated patients tended to be female and non-smoker and experienced a prolonged OS suggesting a possible positive prognostic effect. c-MET mutations did not affect survival. Target therapy might be considered in EGFR and c-MET-mutated patients.

Tao J, Zhang X, Lancet J, et al.
Concurrence of B-lymphoblastic leukemia and myeloproliferative neoplasm with copy neutral loss of heterozygosity at chromosome 1p harboring a MPL W515S mutation.
Cancer Genet. 2014 Oct-Dec; 207(10-12):489-94 [PubMed] Related Publications
B-lymphoblastic leukemia (B-ALL) is a neoplasm of precursors committed to B-cell lineage, whereas myeloproliferative neoplasm (MPN) is a clonal proliferation derived from myeloid stem cells. Concurrent B-ALL with MPN is uncommon except in the presence of abnormalities of the PDGFRA, PDGFRB, or FGFR1 genes or the BCR-ABL1 fusion gene. Herein, we describe a rare concurrence, B-ALL with MPN without the aforementioned genetic aberrations, in a 64-year-old male patient. The patient was initially diagnosed with B-ALL with normal karyotype and responded well to aggressive chemotherapy but had sustained leukocytosis and splenomegaly. The posttreatment restaging bone marrow was free of B-ALL but remained hypercellular with myeloid predominance. Using a single nucleotide polymorphism microarray study, we identified a copy neutral loss of heterozygosity at the terminus of 1p in the bone marrow samples taken at diagnosis and again at remission, 49% and 100%, respectively. Several additional genetic abnormalities were present in the initial marrow sample but not in the remission marrow samples. Retrospective molecular studies detected a MPL W515S homozygous mutation in both the initial and remission marrows for B-ALL, at 30-40% and 80% dosage effect, respectively. In summary, we present a case of concurrent B-ALL and MPN and demonstrate a stepwise cytogenetic and molecular approach to the final diagnosis.

Huang C, Sheng Y, Jia J, Chen L
Identification of melanoma biomarkers based on network modules by integrating the human signaling network with microarrays.
J Cancer Res Ther. 2014; 10 Suppl:C114-24 [PubMed] Related Publications
BACKGROUND: Melanoma is a leading cause of cancer death. Thus, accurate prognostic biomarkers that will assist rational treatment planning need to be identified.
METHODS: Microarray analysis of melanoma and normal tissue samples was performed to identify differentially expressed modules (DEMs) from the signaling network and ultimately detect molecular markers to support histological examination. Network motifs were extracted from the human signaling network. Then, significant expression-correlation differential modules were identified by comparing the network module expression-correlation differential scores under normal and disease conditions using the gene expression datasets. Finally, we obtained DEMs by the Wilcoxon rank test and considered the average gene expression level in these modules as the classification features for diagnosing melanoma.
RESULTS: In total, 99 functional DEMs were identified from the signaling network and gene expression profiles. The area under the curve scores for cancer module genes, melanoma module genes, and whole network modules are 92.4%, 90.44%, and 88.45%, respectively. The classification efficiency rates for nonmodule features are 71.04% and 79.38%, which correspond to the features of cancer genes and melanoma cancer genes, respectively. Finally, we acquired six significant molecular biomarkers, namely, module 10 (CALM3, Ca 2+ , PKC, PDGFRA, phospholipase-g, PIB5PA, and phosphatidylinositol-3-kinase), module 14 (SRC, Src homology 2 domain-containing [SHC], SAM68, GIT1, transcription factor-4, CBLB, GRB2, VAV2, LCK, YES, PTCH2, downstream of tyrosine kinase [DOK], and KIT), module 16 (ELK3, p85beta, SHC, ZFYVE9, TGFBR1, TGFBR2, CITED1, SH3KBP1, HCK, DOK, and KIT), module 45 (RB, CCND3, CCNA2, CDK4, and CDK6), module 75 (PCNA, CDK4, and CCND1), and module 114 (PSD93, NMDAR, and FYN).
CONCLUSION: We explored the gene expression profile and signaling network in a global view and identified DEMs that can be used as diagnostic or prognostic markers for melanoma.

Szasz AM, Szirtes I, Tihanyi B, et al.
Basaloid carcinoma of the pancreas--clinicopathological presentation and oncogenetic snapshot of a rare entity.
Virchows Arch. 2015; 466(2):237-41 [PubMed] Related Publications
We report a case of basaloid pancreatic carcinoma with clinical, pathological, and genomic data. The 73-year-old male patient had jaundice, acholic stool, diarrhea, weight loss, and a large, painless gall bladder. His GGT was highly elevated. The pancreatic head contained a tumor, which was resected by partial pancreatoduodenectomy with pancreato-gastric anastomosis, cholecystectomy, and lymphadenectomy. On gross examination, a 3.8-cm white firm nodule was found, which microscopically was composed of basaloid cell nests with a less than usual desmoplastic stromal background and focally PANIN. Immunohistochemical profile displayed strong CK5/6, CK19, p63, EGFR, vimentin, and evident CK14 expression and absence of expression of CK7, chromogranin, synaptophysin, and BRCA1. A high Ki-67 index and p53 expression were noted. Sequencing of the most frequent 46 oncogenes with ionTorrent (AmpliSeq PCR) method identified PIK3CA, KRAS, and TP53 genes as drivers and variants of the FGFR3, PDGFRA, KIT, KDR, EGFR, RET, and ATM genes. The tumor we report displays histopathological appearances similar to the previously described case and a genomic landscape fitting to the general population of pancreatic carcinomas. We hypothesize that this tumor may belong to the group of DNA damage repair-deficient pancreatic carcinoma subgroup.

Ab Mutalib NS, Syafruddin SE, Md Zain RR, et al.
Molecular characterization of serous ovarian carcinoma using a multigene next generation sequencing cancer panel approach.
BMC Res Notes. 2014; 7:805 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
BACKGROUND: High grade serous ovarian cancer is one of the poorly characterized malignancies. This study aimed to elucidate the mutational events in Malaysian patients with high grade serous ovarian cancer by performing targeted sequencing on 50 cancer hotspot genes.
RESULTS: Nine high grade serous ovarian carcinoma samples and ten normal ovarian tissues were obtained from Universiti Kebangsaan Malaysia Medical Center (UKMMC) and the Kajang Hospital. The Ion AmpliSeq™ Cancer Hotspot Panel v2 targeting "mutation-hotspot region" in 50 most common cancer-associated genes was utilized. A total of 20 variants were identified in 12 genes. Eleven (55%) were silent alterations and nine (45%) were missense mutations. Six of the nine missense mutations were predicted to be deleterious while the other three have low or neutral protein impact. Eight genes were altered in both the tumor and normal groups (APC, EGFR, FGFR3, KDR, MET, PDGFRA, RET and SMO) while four genes (TP53, PIK3CA, STK11 and KIT) were exclusively altered in the tumor group. TP53 alterations were present in all the tumors but not in the normal group. Six deleterious mutations in TP53 (p.R175H, p.H193R, p.Y220C, p.Y163C, p.R282G and p.Y234H) were identified in eight serous ovarian carcinoma samples and none in the normal group.
CONCLUSION: TP53 remains as the most frequently altered gene in high grade serous ovarian cancer and Ion Torrent Personal Genome Machine (PGM) in combination with Ion Ampliseq™ Cancer Hotspot Panel v2 were proven to be instrumental in identifying a wide range of genetic alterations simultaneously from a minute amount of DNA. However, larger series of validation targeting more genes are necessary in order to shed a light on the molecular events underlying pathogenesis of this cancer.

Cenciarelli C, Marei HE, Zonfrillo M, et al.
PDGF receptor alpha inhibition induces apoptosis in glioblastoma cancer stem cells refractory to anti-Notch and anti-EGFR treatment.
Mol Cancer. 2014; 13:247 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
BACKGROUND: Cancer stem cells (CSC) represent a rare fraction of cancer cells characterized by resistance to chemotherapy and radiation, therefore nowadays there is great need to develop new targeted therapies for brain tumors and our study aim to target pivotal transmembrane receptors such as Notch, EGFR and PDGFR, which are already under investigation in clinical trials setting for the treatment of Glioblastoma Multiforme (GBM).
METHODS: MTS assay was performed to evaluate cells response to pharmacological treatments. Quantitative RT-PCR and Western blots were performed to state the expression of Notch1, EGFR and PDGFRα/β and the biological effects exerted by either single or combined targeted therapy in GBM CSC. GBM CSC invasive ability was tested in vitro in absence or presence of Notch and/or EGFR signaling inhibitors.
RESULTS: In this study, we investigated gene expression and function of Notch1, EGFR and PDGFR to determine their role among GBM tumor core- (c-CSC) vs. peritumor tissue-derived cancer stem cells (p-CSC) of six cases of GBM. Notch inhibition significantly impaired cell growth of c-CSC compared to p-CSC pools, with no effects observed in cell cycle distribution, apoptosis and cell invasion assays. Instead, anti-EGFR therapy induced cell cycle arrest, sometimes associated with apoptosis and reduction of cell invasiveness in GBM CSC. In two cases, c-CSC pools were more sensitive to simultaneous anti-Notch and anti-EGFR treatment than either therapy alone compared to p-CSC, which were mostly resistant to treatment. We reported the overexpression of PDGFRα and its up-regulation following anti-EGFR therapy in GBM p-CSC compared to c-CSC. RNA interference of PDGFRα significantly reduced cell proliferation rate of p-CSC, while its pharmacological inhibition with Crenolanib impaired survival of both CSC pools, whose effects in combination with EGFR inhibition were maximized.
CONCLUSIONS: We have used different drugs combination to identify the more effective therapeutic targets for GBM CSC, particularly against GBM peritumor tissue-derived CSC, which are mostly resistant to treatments. Overall, our results provide the rationale for simultaneous targeting of EGFR and PDGFR, which would be beneficial in the treatment of GBM.

Akçakaya P, Caramuta S, Åhlen J, et al.
microRNA expression signatures of gastrointestinal stromal tumours: associations with imatinib resistance and patient outcome.
Br J Cancer. 2014; 111(11):2091-102 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
BACKGROUND: Gastrointestinal stromal tumour (GIST) is mainly initialised by receptor tyrosine kinase gene mutations. Although the tyrosine kinase inhibitor imatinib mesylate considerably improved the outcome of patients, imatinib resistance still remains a major therapeutic challenge in GIST therapy. Herein we evaluated the clinical impact of microRNAs in imatinib-treated GISTs.
METHODS: The expression levels of microRNAs were quantified using microarray and RT-qPCR in GIST specimens from patients treated with neoadjuvant imatinib. The functional roles of miR-125a-5p and PTPN18 were evaluated in GIST cells. PTPN18 expression was quantified by western blotting in GIST samples.
RESULTS: We showed that overexpression levels of miR-125a-5p and miR-107 were associated with imatinib resistance in GIST specimens. Functionally, miR-125a-5p expression modulated imatinib sensitivity in GIST882 cells with a homozygous KIT mutation but not in GIST48 cells with double KIT mutations. Overexpression of miR-125a-5p suppressed PTPN18 expression, and silencing of PTPN18 expression increased cell viability in GIST882 cells upon imatinib treatment. PTPN18 protein levels were significantly lower in the imatinib-resistant GISTs and inversely correlated with miR-125a-5p. Furthermore, several microRNAs were significantly associated with metastasis, KIT mutational status and survival.
CONCLUSIONS: Our findings highlight a novel functional role of miR-125a-5p on imatinib response through PTPN18 regulation in GIST.

Wei T, Zhang LN, Lv Y, et al.
Overexpression of platelet-derived growth factor receptor alpha promotes tumor progression and indicates poor prognosis in hepatocellular carcinoma.
Oncotarget. 2014; 5(21):10307-17 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
Dysregulation of platelet-derived growth factor receptor alpha (PDGFRα) has been documented in various cancers. However, its role in hepatocellular carcinoma (HCC) remains unknown. We and others have examined that upregulation of PDGFRα might be involved in hepatocarcinogenesis. Here, we report that PDGFRα plays a critical role in HCC progression and prognosis. The expression of PDGFRα was markedly higher in human HCC compared to adjacent liver tissues. Although PDGFRA mRNA was decreased in HCC, PDGF-A mRNA was dramatically increased in HCC. Overexpression of PDGFRα was strongly correlated with microvessel density (MVD) of HCC (p<0.05), as well as macroscopic vascular invasion of the tumors (p<0.05). HCC patients with high PDGFRα expression displayed a shorter overall survival and a higher recurrence rate than those with low PDGFRα expression (p<0.05, respectively). Additionally, stable overexpression of PDGFRα in hepatoma cells promoted cell proliferation, migration, invasion and epithelial-mesenchymal transition in vitro. Similarly, an in vivo assay showed that PDGFRα overexpression in hepatoma cells exhibited remarkably tumorigenic potential in tumor size and weight in vivo, which displayed markedly elevated MVD than controls. Thus, our study provided the evidence that PDGFRα may serve as a candidate prognostic marker and a novel therapeutic target for HCC.

Wozniak A, Rutkowski P, Schöffski P, et al.
Tumor genotype is an independent prognostic factor in primary gastrointestinal stromal tumors of gastric origin: a european multicenter analysis based on ConticaGIST.
Clin Cancer Res. 2014; 20(23):6105-16 [PubMed] Related Publications
PURPOSE: Although the mutational status in gastrointestinal stromal tumors (GIST) can predict the response to treatment with tyrosine kinase inhibitors, the role of tumor genotype as a prognostic factor remains controversial. The ConticaGIST study sought to determine the pathologic and molecular factors associated with disease-free survival (DFS) in patients with operable, imatinib-naive GIST.
EXPERIMENTAL DESIGN: Clinicopathologic and molecular data from 1,056 patients with localized GIST who underwent surgery with curative intention (R0/R1) and were registered in the European ConticaGIST database were prospectively obtained and reviewed. Risk of tumor recurrence was stratified using the modified NIH criteria. The median follow-up was 52 months.
RESULTS: On testing for potential prognostic parameters, the following were associated with inferior DFS on multivariable Cox model analysis: primary nongastric site, size >10 cm, mitotic index >10 mitoses per 50 high power field, and the KIT exon 9 duplication [hazard ratio (HR), 1.47; 95% confidence interval (CI), 0.9-2.5; P = 0.037] and KIT exon 11 deletions involving codons 557 and/or 558 [KITdel-inc557/558; HR, 1.45; 95% CI, 1.0-2.2; P = 0.004]. Conversely, PDGFRA exon 18 mutations were indicators of better prognosis [HR, 0.23; 95% CI, 0.1-0.6; P = 0.002]. KITdel-inc557/558 were an adverse indicator only in GIST localized in the stomach (P < 0.001) but not in tumors with nongastric origin. In gastric GIST, all other mutations presented remarkably superior 5-year DFS.
CONCLUSIONS: In conclusion, tumor genotype is an independent molecular prognostic variable associated with gastric GIST and should be used for optimizing tailored adjuvant imatinib treatment.

Bian L, Wang Y, Liu Q, et al.
Prediction of signaling pathways involved in enterovirus 71 infection by algorithm analysis based on miRNA profiles and their target genes.
Arch Virol. 2015; 160(1):173-82 [PubMed] Related Publications
Enterovirus 71 (EV71) causes major outbreaks of hand, foot, and mouth disease. Host factors and signaling pathways exhibit important functions in the EV71 life cycle. We conducted algorithm analysis based on miRNA profiles and their target genes to identify the miRNAs and downstream signaling pathways involved in EV71 infection. The miRNA profiles of human rhabdomyosarcoma cells treated with interferon (IFN-)-α or IFN-γ were compared with those of cells infected with EV71. Genes targeted by differentially expressed miRNAs were identified and assigned to different signaling pathways according to public databases. The results showed that host miRNAs specifically responded to the viral infection and IFN treatment. Some miRNAs, including miR-124 and miR-491-3p, were regulated in opposite manners by the IFNs and EV71. Some signaling pathways regulated by both EV71 infection and IFN treatment were also predicted. These pathways included axon guidance, Wingless/Int1 (Wnt) signaling cascade, platelet-derived growth factor receptor (PDGFR)/PDGF, phosphatidylinositol 3-kinase (PI3K), Jun N-terminal kinase (JNK)/mitogen-activated protein kinase (MAPK), transforming growth factor-beta receptor (TGF-βR)/TGF-β, SMAD2/3, insulin/insulin-like growth factor (IGF), bone morphogenetic protein (BMP), CDC42, ERB1, hepatocyte growth factor receptor (c-Met), eukaryotic translation initiation factor 4E (eIF4E), protein kinase A (PKA), and IFN-γ pathways. The identified miRNA and downstream signaling pathways would help to elucidate the interaction between the virus and the host. The genomics method using algorithm analysis also provided a new way to investigate the host factors and signaling pathways critical for viral replication.

Shitara M, Okuda K, Suzuki A, et al.
Genetic profiling of thymic carcinoma using targeted next-generation sequencing.
Lung Cancer. 2014; 86(2):174-9 [PubMed] Related Publications
OBJECTIVES: Thymic carcinoma is a rare mediastinal neoplasm and little is known about its tumorigenesis. There is no effective treatment except for complete resection, and the prognosis of advanced cases is poor. To identify the mutations associated with tumorigenesis, we analyzed genetic profile of thymic carcinoma using targeted next-generation sequencing.
MATERIALS AND METHODS: We sequenced about 409 cancer-related genes in 12 thymic squamous cell carcinoma tissues including 10 tumor/normal tissue pairs using Ion AmpliSeq Cancer Panel and Ion PGM Sequencer. We filtered the mutations with Ingenuity Variant Analysis, SIFT, PolyPhen-2, and PROVEAN.
RESULTS AND CONCLUSION: Twenty-five candidate mutations in 24 genes were identified, including five tyrosine kinase genes (KIT, DDR2, PDGFRA, ROS1, IGF1R). There was no recurrent mutation among the samples studied. The KIT exon 11 deletion mutation in 1 patient was an activating mutation and may be an oncogenic driver mutation. Genetic profiling of thymic carcinoma using targeted next-generation sequencing was performed. The mutation status of thymic squamous cell carcinoma is highly heterogeneous.

Eng KH, Ruggeri C
Connecting prognostic ligand receptor signaling loops in advanced ovarian cancer.
PLoS One. 2014; 9(9):e107193 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
Understanding cancer cell signal transduction is a promising lead for uncovering therapeutic targets and building treatment-specific markers for epithelial ovarian cancer. To brodaly assay the many known transmembrane receptor systems, previous studies have employed gene expression data measured on high-throughput microarrays. Starting with the knowledge of validated ligand-receptor pairs (LRPs), these studies postulate that correlation of the two genes implies functional autocrine signaling. It is our goal to consider the additional weight of evidence that prognosis (progression-free survival) can bring to prioritize ovarian cancer specific signaling mechanism. We survey three large studies of epithelial ovarian cancers, with gene expression measurements and clinical information, by modeling survival times both categorically (long/short survival) and continuously. We use differential correlation and proportional hazards regression to identify sets of LRPs that are both prognostic and correlated. Of 475 candidate LRPs, 77 show reproducible evidence of correlation; 55 show differential correlation. Survival models identify 16 LRPs with reproduced, significant interactions. Only two pairs show both interactions and correlation (PDGFA[Formula: see text]PDGFRA and COL1A1[Formula: see text]CD44) suggesting that the majority of prognostically useful LRPs act without positive feedback. We further assess the connectivity of receptors using a Gaussian graphical model finding one large graph and a number of smaller disconnected networks. These LRPs can be organized into mutually exclusive signaling clusters suggesting different mechanisms apply to different patients. We conclude that a mix of autocrine and endocrine LRPs influence prognosis in ovarian cancer, there exists a heterogenous mix of signaling themes across patients, and we point to a number of novel applications of existing targeted therapies which may benefit ovarian cancer.

Nannini M, Astolfi A, Urbini M, et al.
Integrated genomic study of quadruple-WT GIST (KIT/PDGFRA/SDH/RAS pathway wild-type GIST).
BMC Cancer. 2014; 14:685 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
BACKGROUND: About 10-15% of adult gastrointestinal stromal tumors (GIST) and the vast majority of pediatric GIST do not harbour KIT or platelet-derived growth factor receptor alpha (PDGFRA) mutations (J Clin Oncol 22:3813-3825, 2004; Hematol Oncol Clin North Am 23:15-34, 2009). The molecular biology of these GIST, originally defined as KIT/PDGFRA wild-type (WT), is complex due to the existence of different subgroups with distinct molecular hallmarks, including defects in the succinate dehydrogenase (SDH) complex and mutations of neurofibromatosis type 1 (NF1), BRAF, or KRAS genes (RAS-pathway or RAS-P).In this extremely heterogeneous landscape, the clinical profile and molecular abnormalities of the small subgroup of WT GIST suitably referred to as quadruple wild-type GIST (quadrupleWT or KITWT/PDGFRAWT/SDHWT/RAS-PWT) remains undefined. The aim of this study is to investigate the genomic profile of KITWT/PDGFRAWT/SDHWT/RAS-PWT GIST, by using a massively parallel sequencing and microarray approach, and compare it with the genomic profile of other GIST subtypes.
METHODS: We performed a whole genome analysis using a massively parallel sequencing approach on a total of 16 GIST cases (2 KITWT/PDGFRAWT/SDHWT and SDHBIHC+/SDHAIHC+, 2 KITWT/PDGFRAWT/SDHAmut and SDHBIHC-/SDHAIHC- and 12 cases of KITmut or PDGFRAmut GIST). To confirm and extend the results, whole-genome gene expression analysis by microarray was performed on 9 out 16 patients analyzed by RNAseq and an additional 20 GIST patients (1 KITWT/PDGFRAWTSDHAmut GIST and 19 KITmut or PDGFRAmut GIST). The most impressive data were validated by quantitave PCR and Western Blot analysis.
RESULTS: We found that both cases of quadrupleWT GIST had a genomic profile profoundly different from both either KIT/PDGFRA mutated or SDHA-mutated GIST. In particular, the quadrupleWT GIST tumors are characterized by the overexpression of molecular markers (CALCRL and COL22A1) and of specific oncogenes including tyrosine and cyclin- dependent kinases (NTRK2 and CDK6) and one member of the ETS-transcription factor family (ERG).
CONCLUSION: We report for the first time an integrated genomic picture of KITWT/PDGFRAWT/SDHWT/RAS-PWT GIST, using massively parallel sequencing and gene expression analyses, and found that quadrupleWT GIST have an expression signature that is distinct from SDH-mutant GIST as well as GIST harbouring mutations in KIT or PDGFRA. Our findings suggest that quadrupleWT GIST represent another unique group within the family of gastrointestintal stromal tumors.

Ali NA, Wu J, Hochgräfe F, et al.
Profiling the tyrosine phosphoproteome of different mouse mammary tumour models reveals distinct, model-specific signalling networks and conserved oncogenic pathways.
Breast Cancer Res. 2014; 16(5):437 [PubMed] Article available free on PMC after 20/03/2016 Related Publications
INTRODUCTION: Although aberrant tyrosine kinase signalling characterises particular breast cancer subtypes, a global analysis of tyrosine phosphorylation in mouse models of breast cancer has not been undertaken to date. This may identify conserved oncogenic pathways and potential therapeutic targets.
METHODS: We applied an immunoaffinity/mass spectrometry workflow to three mouse models: murine stem cell virus-Neu, expressing truncated Neu, the rat orthologue of human epidermal growth factor receptor 2, Her2 (HER2); mouse mammary tumour virus-polyoma virus middle T antigen (PyMT); and the p53-/- transplant model (p53). Pathways and protein-protein interaction networks were identified by bioinformatics analysis. Molecular mechanisms underpinning differences in tyrosine phosphorylation were characterised by Western blot analysis and array comparative genomic hybridisation. The functional role of mesenchymal-epithelial transition factor (Met) in a subset of p53-null tumours was interrogated using a selective tyrosine kinase inhibitor (TKI), small interfering RNA (siRNA)-mediated knockdown and cell proliferation assays.
RESULTS: The three models could be distinguished on the basis of tyrosine phosphorylation signatures and signalling networks. HER2 tumours exhibited a protein-protein interaction network centred on avian erythroblastic leukaemia viral oncogene homologue 2 (Erbb2), epidermal growth factor receptor and platelet-derived growth factor receptor α, and they displayed enhanced tyrosine phosphorylation of ERBB receptor feedback inhibitor 1. In contrast, the PyMT network displayed significant enrichment for components of the phosphatidylinositol 3-kinase signalling pathway, whereas p53 tumours exhibited increased tyrosine phosphorylation of Met and components or regulators of the cytoskeleton and shared signalling network characteristics with basal and claudin-low breast cancer cells. A subset of p53 tumours displayed markedly elevated cellular tyrosine phosphorylation and Met expression, as well as Met gene amplification. Treatment of cultured p53-null cells exhibiting Met amplification with a selective Met TKI abrogated aberrant tyrosine phosphorylation and blocked cell proliferation. The effects on proliferation were recapitulated when Met was knocked down using siRNA. Additional subtypes of p53 tumours exhibited increased tyrosine phosphorylation of other oncogenes, including Peak1/SgK269 and Prex2.
CONCLUSION: This study provides network-level insights into signalling in the breast cancer models utilised and demonstrates that comparative phosphoproteomics can identify conserved oncogenic signalling pathways. The Met-amplified, p53-null tumours provide a new preclinical model for a subset of triple-negative breast cancers.

Soria JC, DeBraud F, Bahleda R, et al.
Phase I/IIa study evaluating the safety, efficacy, pharmacokinetics, and pharmacodynamics of lucitanib in advanced solid tumors.
Ann Oncol. 2014; 25(11):2244-51 [PubMed] Related Publications
BACKGROUND: Lucitanib is a potent, oral inhibitor fibroblast growth factor receptor types 1 and 2 (FGFR), vascular endothelial growth factor receptor types 1, 2, and 3 (VEGFR), platelet-derived growth factor receptor types α and β (PGFRα/β), which are essential kinases for tumor growth, survival, migration, and angiogenesis. Several tumor types, including breast carcinoma, demonstrate amplification of fibroblast growth factor (FGF)-related genes. There are no approved drugs for molecularly defined FGF-aberrant (FGFR1- or FGF3/4/19-amplified) tumors.
METHODS: This open-label phase I/IIa study involved a dose-escalation phase to determine maximum tolerated dose (MTD), recommended dose (RD), and pharmacokinetics of lucitanib in patients with advanced solid tumors, followed by a dose-expansion phase to obtain preliminary evidence of efficacy in patients who could potentially benefit from treatment (i.e. with tumors harboring FGF-aberrant pathway or considered angiogenesis-sensitive).
RESULTS: Doses from 5 to 30 mg were evaluated with dose-limiting toxic effects dominated by vascular endothelial growth factor (VEGF) inhibition-related toxic effects at the 30 mg dose level (one case of grade 4 depressed level of consciousness and two cases of grade 3 thrombotic microangiopathy). The most common adverse events (all grades, all cohorts) were hypertension (91%), asthenia (42%), and proteinuria (57%). Exposure increased with dose and t½ was 31-40 h, suitable for once daily administration. Seventy-six patients were included. All but one had stage IV; 42% had >3 lines of previous chemotherapy. Sixty-four patients were assessable for response; 58 had measurable disease. Clinical activity was observed at all doses tested with durable Response Evaluation Criteria In Solid Tumors (RECIST) partial responses in a variety of tumor types. In the angiogenesis-sensitive group, objective RECIST response rate (complete response + partial response) was 26% (7 of 27) and progression-free survival (PFS) was 25 weeks. In assessable FGF-aberrant breast cancer patients, 50% (6 of 12) achieved RECIST partial response with a median PFS of 40.4 weeks for all treated patients.
CONCLUSION: Lucitanib has promising efficacy and a manageable side-effect profile. The spectrum of activity observed demonstrates clinical benefit in both FGF-aberrant and angiogenesis-sensitive populations. A comprehensive phase II program is planned.

Liu C, Li J, Xiang X, et al.
PDGF receptor-α promotes TGF-β signaling in hepatic stellate cells via transcriptional and posttranscriptional regulation of TGF-β receptors.
Am J Physiol Gastrointest Liver Physiol. 2014; 307(7):G749-59 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
Platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β) signaling are required for hepatic stellate cell (HSC) activation under pathological conditions such as liver metastatic tumor growth. These two signaling pathways are functionally divergent; PDGF signaling promotes proliferation and migration of HSCs, and TGF-β induces transdifferentiation of quiescent HSCs into myofibroblasts. Although PDGF signaling is implicated in TGF-β-mediated epithelial mesenchymal transition of tumor cells, the role of PDGF receptors in TGF-β activation of HSCs has not been investigated. Here we report that PDGF receptor-α (PDGFR-α) is required for TGF-β signaling of cultured human HSCs although HSCs express both PDGF-α and -β receptors. PDGFR-α knockdown inhibits TGF-β-induced phosphorylation and nuclear accumulation of SMAD2 with no influence on AKT or ERK phosphorylation associated with noncanonical TGF-β signaling. PDGFR-α knockdown suppresses TGF-β receptor I (TβRI) but increases TβRII gene transcription. At the protein level, PDGFR-α is recruited to TβRI/TβRII complexes by TGF-β stimulation. PDGFR-α knockdown blocks TGF-β-mediated internalization of TβRII and induces accumulation of TβRII at the plasma membrane, thereby inhibiting TGF-β phosphorylation of SMAD2. Functionally, knockdown of PDGFR-α reduces paracrine effects of HSCs on colorectal cancer cell proliferation and migration in vitro. In mice and patients, colorectal cancer cell invasion of the liver induces upregulation of PDGFR-α of HSCs. In summary, our finding that PDGFR-α knockdown inhibits SMAD-dependent TGF-β signaling by repressing TβRI transcriptionally and blocking endocytosis of TGF-β receptors highlights a convergence of PDGF and TGF-β signaling for HSC activation and PDGFR-α as a therapeutic target for liver metastasis and other settings of HSC activation.

Zhu Y, Wang Y, Guan B, et al.
C-kit and PDGFRA gene mutations in triple negative breast cancer.
Int J Clin Exp Pathol. 2014; 7(7):4280-5 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
In this study, we evaluated C-kit immunohistochemical expression and C-kit and platelet derived growth factor receptor A (PDGFRA) gene mutations in triple negative breast cancer. 171 cases were analyzed by immunohistochemical staining for the expression of C-kit and 45 cases, including 10 C-kit negative cases and 35 C-kit positive cases, were performed for C-kit gene mutations in exons 9, 11, 13 and 17 and PDGFRA gene mutations in exons 12 and 18. C-kit expression was detected in 42.1% of triple negative breast cancers. Only 1 activating mutation was detected in exon 11 of C-kit gene in 1 case. No activating mutations were found in the other 44 cases. C-kit expression is a frequent finding in triple negative breast cancers; 1 activating mutation which was also found in gastrointestinal stromal tumors was detected; a few cases might benefit from imatinib.

Ozawa T, Riester M, Cheng YK, et al.
Most human non-GCIMP glioblastoma subtypes evolve from a common proneural-like precursor glioma.
Cancer Cell. 2014; 26(2):288-300 [PubMed] Free Access to Full Article Related Publications
To understand the relationships between the non-GCIMP glioblastoma (GBM) subgroups, we performed mathematical modeling to predict the temporal sequence of driver events during tumorigenesis. The most common order of evolutionary events is 1) chromosome (chr) 7 gain and chr10 loss, followed by 2) CDKN2A loss and/or TP53 mutation, and 3) alterations canonical for specific subtypes. We then developed a computational methodology to identify drivers of broad copy number changes, identifying PDGFA (chr7) and PTEN (chr10) as driving initial nondisjunction events. These predictions were validated using mouse modeling, showing that PDGFA is sufficient to induce proneural-like gliomas and that additional NF1 loss converts proneural to the mesenchymal subtype. Our findings suggest that most non-GCIMP mesenchymal GBMs arise as, and evolve from, a proneural-like precursor.

Boikos SA, Stratakis CA
The genetic landscape of gastrointestinal stromal tumor lacking KIT and PDGFRA mutations.
Endocrine. 2014; 47(2):401-8 [PubMed] Related Publications
About 10-15 % of adult gastrointestinal stromal tumors (GISTs) and 85 % of pediatric GISTs do not have mutations in the KIT or PDGFRA genes and are generally classified as KIT/PDGFRA wild type (WT). Recent studies have shown that this group of KIT/PDGFRA WT GISTs is quite heterogeneous in terms of clinical phenotype, genetic etiology, and molecular pathways. Succinate dehydrogenase subunit (SDH)-deficient GISTs, which include tumors that are part of multiple endocrine neoplasia syndromes, are the newest group of KIT/PDGFRA WT GIST to be molecularly elucidated. This review aims to describe the different genetic subgroups of KIT/PDGFRA WT GIST, with a special focus on the SDH-deficient GIST.

Salvi S, Calistri D, Gurioli G, et al.
Copy number analysis of 24 oncogenes: MDM4 identified as a putative marker for low recurrence risk in non muscle invasive bladder cancer.
Int J Mol Sci. 2014; 15(7):12458-68 [PubMed] Free Access to Full Article Related Publications
Patients with non-muscle invasive bladder cancer (NMIBC) generally have a high risk of relapsing locally after primary tumor resection. The search for new predictive markers of local recurrence thus represents an important goal for the management of this disease. We studied the copy number variations (CNVs) of 24 oncogenes (MDM4, MYCN, ALK, PDGFRA, KIT, KDR, DHFR, EGFR, MET, SMO, FGFR1, MYC, ABL1, RET, CCND1, CCND2, CDK4, MDM2, AURKB, ERBB2, TOP2A, AURKA, AR and BRAF) using multiplex ligation probe amplification technique to verify their role as predictive markers of recurrence. Formalin-fixed paraffin-embedded tissue samples from 43 patients who underwent transurethral resection of the bladder (TURB) were used; 23 patients had relapsed and 20 were disease-free after 5 years. Amplification frequencies were analyzed for all genes and MDM4 was the only gene that showed significantly higher amplification in non recurrent patients than in recurrent ones (0.65 vs. 0.3; Fisher's test p=0.023). Recurrence-free survival analysis confirmed the predictive role of MDM4 (log-rank test p=0.041). Our preliminary results indicate a putative role for the MDM4 gene in predicting local recurrence of bladder cancer. Confirmation of this hypothesis is needed in a larger cohort of NMIBC patients.

Jansson S, Bendahl PO, Grabau DA, et al.
The three receptor tyrosine kinases c-KIT, VEGFR2 and PDGFRα, closely spaced at 4q12, show increased protein expression in triple-negative breast cancer.
PLoS One. 2014; 9(7):e102176 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Triple-negative breast cancer (TNBC) is a heterogeneous subgroup of breast cancer with poor prognosis and no targeted therapy available. Receptor tyrosine kinases (RTKs) are emerging targets in anticancer therapy and many RTK-inhibiting drugs are currently being developed. The aim of this study was to elucidate if there is a correlation between the protein expression of three RTKs c-KIT, VEGFR2 and PDGFRα, their gene copy number, and prognosis in TNBC compared to non-TNBC.
METHODS: Tumor tissue samples from patients diagnosed with primary breast cancer were stained with immunohistochemistry (IHC) for protein assessment, and with fluorescence in situ hybridization (FISH) for gene copy number determination. Breast cancer mortality (BCM), measured from the date of surgery to death, was used as endpoint.
RESULTS: The cohort included 464 patients, out of which 34 (7.3%) had a TNBC. High expression of the three RTKs was more common in TNBC compared to non-TNBC: c-KIT 49% vs. 10% (P<0.001), PDGFRα 32% vs. 19% (P = 0.07) and VEGFR2 32% vs. 6% (P<0.001). The odds ratio (OR) of c-KIT, VEGFR2 and PDGFRα positivity, adjusted for tumor characteristics, was 6.8, 3.6 and 1.3 times higher for TNBC than for non-TNBC. 73.5% of the TNBC had high expression of at least one of the three investigated receptors, compared to 30.0% of the non-TNBC (P<0.001). Survival analysis showed no significant difference in BCM for TNBC patients with high vs. low c-KIT, PDGFRα or VEGFR2 protein expression. 193 (42%) tumors were evaluated with FISH. No correlation was seen between increased gene copy number and TNBC, or between increased gene copy number and high protein expression of the RTK.
CONCLUSION: c-KIT, VEGFR2 and PDGFRα show higher protein expression in TNBC compared to non-TNBC. Further investigation clarifying the importance of these RTKs in TNBC is encouraged, as they are possible targets for anticancer therapy.

Further References

Cools J, DeAngelo DJ, Gotlib J, et al.
A tyrosine kinase created by fusion of the PDGFRA and FIP1L1 genes as a therapeutic target of imatinib in idiopathic hypereosinophilic syndrome.
N Engl J Med. 2003; 348(13):1201-14 [PubMed] Related Publications
BACKGROUND: Idiopathic hypereosinophilic syndrome involves a prolonged state of eosinophilia associated with organ dysfunction. It is of unknown cause. Recent reports of responses to imatinib in patients with the syndrome suggested that an activated kinase such as ABL, platelet-derived growth factor receptor (PDGFR), or KIT, all of which are inhibited by imatinib, might be the cause.
METHODS: We treated 11 patients with the hypereosinophilic syndrome with imatinib and identified the molecular basis for the response.
RESULTS: Nine of the 11 patients treated with imatinib had responses lasting more than three months in which the eosinophil count returned to normal. One such patient had a complex chromosomal abnormality, leading to the identification of a fusion of the Fip1-like 1 (FIP1L1) gene to the PDGFRalpha (PDGFRA) gene generated by an interstitial deletion on chromosome 4q12. FIP1L1-PDGFRalpha is a constitutively activated tyrosine kinase that transforms hematopoietic cells and is inhibited by imatinib (50 percent inhibitory concentration, 3.2 nM). The FIP1L1-PDGFRA fusion gene was subsequently detected in 9 of 16 patients with the syndrome and in 5 of the 9 patients with responses to imatinib that lasted more than three months. Relapse in one patient correlated with the appearance of a T674I mutation in PDGFRA that confers resistance to imatinib.
CONCLUSIONS: The hypereosinophilic syndrome may result from a novel fusion tyrosine kinase - FIP1L1-PDGFRalpha - that is a consequence of an interstitial chromosomal deletion. The acquisition of a T674I resistance mutation at the time of relapse demonstrates that FIP1L1-PDGFRalpha is the target of imatinib. Our data indicate that the deletion of genetic material may result in gain-of-function fusion proteins.

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