Gene Summary

Gene:KRAS; Kirsten rat sarcoma viral oncogene homolog
Summary:This gene, a Kirsten ras oncogene homolog from the mammalian ras gene family, encodes a protein that is a member of the small GTPase superfamily. A single amino acid substitution is responsible for an activating mutation. The transforming protein that results is implicated in various malignancies, including lung adenocarcinoma, mucinous adenoma, ductal carcinoma of the pancreas and colorectal carcinoma. Alternative splicing leads to variants encoding two isoforms that differ in the C-terminal region. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:GTPase KRas
Source:NCBIAccessed: 26 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 26 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 26 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (10)

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

Entity Topic PubMed Papers
Colorectal CancerKRAS and Colorectal Cancer View Publications1685
Lung CancerKRAS and Lung Cancer View Publications989
Lung Cancer, Non-Small CellKRAS and Non-Small Cell Lung Cancer View Publications512
Pancreatic CancerKRAS and Pancreatic Cancer View Publications421
Thyroid CancerKRAS and Thyroid Cancer View Publications97
Stomach CancerKRAS and Stomach Cancer View Publications96
Skin CancerKRAS and Skin Cancer View Publications87
Noonan SyndromeKRAS mutation in Noonan Syndrome
Noonan Syndrome is an autosamal dominant multi-system disorder, characterised by facial anomalies, short stature, developmental delay, cardiac abnormalities and other symptoms. The syndrome pre-disposes to myeloproliferative disorders ( mainly chronic myeolomonocytic leukemia / juvenile myelomonocytic leukemia and acute lymphoblastic leukemia), with reports of neuroblastoma, rhabdomyosarcoma and a wide range of other tumors.
View Publications14
-KRAS and Noonan Syndrome View Publications13
Urinary System CancersKRAS and Urinary System Cancers View Publications71

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

Latest Publications: KRAS (cancer-related)

Xie CM, Wei D, Zhao L, et al.
Erbin is a novel substrate of the Sag-βTrCP E3 ligase that regulates KrasG12D-induced skin tumorigenesis.
J Cell Biol. 2015; 209(5):721-37 [PubMed] Article available free on PMC after 08/12/2015 Related Publications
SAG/RBX2 is the RING (really interesting new gene) component of Cullin-RING ligase, which is required for its activity. An organ-specific role of SAG in tumorigenesis is unknown. We recently showed that Sag/Rbx2, upon lung-targeted deletion, suppressed Kras(G12D)-induced tumorigenesis via inactivating NF-κB and mammalian target of rapamycin pathways. In contrast, we report here that, upon skin-targeted deletion, Sag significantly accelerated Kras(G12D)-induced papillomagenesis. In Kras(G12D)-expressing primary keratinocytes, Sag deletion promotes proliferation by inhibiting autophagy and senescence, by inactivating the Ras-Erk pathway, and by blocking reactive oxygen species (ROS) generation. This is achieved by accumulation of Erbin to block Ras activation of Raf and Nrf2 to scavenge ROS and can be rescued by knockdown of Nrf2 or Erbin. Simultaneous one-allele deletion of the Erbin-encoding gene Erbb2ip partially rescued the phenotypes. Finally, we characterized Erbin as a novel substrate of SAG-βTrCP E3 ligase. By degrading Erbin and Nrf2, Sag activates the Ras-Raf pathway and causes ROS accumulation to trigger autophagy and senescence, eventually delaying Kras(G12D)-induced papillomagenesis and thus acting as a skin-specific tumor suppressor.

Whittle MC, Izeradjene K, Rani PG, et al.
RUNX3 Controls a Metastatic Switch in Pancreatic Ductal Adenocarcinoma.
Cell. 2015; 161(6):1345-60 [PubMed] Article available free on PMC after 04/06/2016 Related Publications
For the majority of patients with pancreas cancer, the high metastatic proclivity is life limiting. Some patients, however, present with and succumb to locally destructive disease. A molecular understanding of these distinct disease manifestations can critically inform patient management. Using genetically engineered mouse models, we show that heterozygous mutation of Dpc4/Smad4 attenuates the metastatic potential of Kras(G12D/+);Trp53(R172H/+) pancreatic ductal adenocarcinomas while increasing their proliferation. Subsequent loss of heterozygosity of Dpc4 restores metastatic competency while further unleashing proliferation, creating a highly lethal combination. Expression levels of Runx3 respond to and combine with Dpc4 status to coordinately regulate the balance between cancer cell division and dissemination. Thus, Runx3 serves as both a tumor suppressor and promoter in slowing proliferation while orchestrating a metastatic program to stimulate cell migration, invasion, and secretion of proteins that favor distant colonization. These findings suggest a model to anticipate likely disease behaviors in patients and tailor treatment strategies accordingly.

Bettington ML, Chetty R
Traditional serrated adenoma: an update.
Hum Pathol. 2015; 46(7):933-8 [PubMed] Related Publications
Although recognized 25 years ago, the traditional serrated adenoma (TSA) remains an ongoing source of diagnostic and biologic debate. Recent research has greatly improved our understanding of the morphological and molecular aspects of these polyps. In particular, the recognition of ectopic crypt foci (ECFs) in combination with typical cytology and slitlike serrations improves diagnostic reproducibility. Awareness that many TSAs, particularly BRAF-mutated TSAs, arise in precursor microvesicular hyperplastic polyps and sessile serrated adenomas can aid in making this diagnosis and should not be confused with a sessile serrated adenoma with dysplasia. At a molecular level, TSAs can be divided into 2 groups based on their BRAF or KRAS mutation status. The development of overt cytologic dysplasia is accompanied by TP53 mutation, Wnt pathway activation, and, in some cases, silencing of CDKN2A. Importantly, however, mismatch repair enzyme function is retained. Thus, the TSA is an important precursor of aggressive molecular subtypes of colorectal carcinoma.

Zhang H, Zhang X, Wang J, et al.
Comparison of high-resolution melting analysis, Sanger sequencing and ARMS for KRAS mutation detection in metastatic colorectal cancer.
Clin Lab. 2015; 61(3-4):435-9 [PubMed] Related Publications
BACKGROUND: Treatment of metastatic colon carcinoma with the anti-epidermal growth factor receptor antibody cetuximab/panitumumab is reported to be ineffective in KRAS-mutant tumors; therefore, it is necessary to perform KRAS mutation analysis before cetuximab or panitumumab treatment is initiated.
METHODS: This study was designed to compare and evaluate the efficacy of three different methodologies--high resolution melting (HRM), Sanger sequencing, and Amplification Refractory Mutation System (ARMS)--for KRAS mutation detection in a clinical setting.
RESULTS: In total, 55 samples from patients with metastatic colorectal cancer were analyzed. Compared to Sanger sequencing, good consistency was found between the results of the ARMS (Kappa = 0.839) and HRM (Kappa = 0.839). The sensitivities of the methods were compared after a consensus was reached: if two of the three methodologies showed a similar result, it was considered as the consensus result. The frequency of KRAS mutations in our population was 34.5%, and discordant findings were observed in five samples. No significant difference in sensitivity was found among the three methodologies.
CONCLUSIONS: From the results, we can conclude that after careful in-laboratory validation, HRM is a good alternative to the ARMS and Sanger sequencing for KRAS mutation testing.

Gleeson FC, Kipp BR, Voss JS, et al.
Endoscopic ultrasound fine-needle aspiration cytology mutation profiling using targeted next-generation sequencing: personalized care for rectal cancer.
Am J Clin Pathol. 2015; 143(6):879-88 [PubMed] Related Publications
OBJECTIVES: In an era of precision medicine, our aim was to determine the frequency and theranostic potential of mutations identified in malignant lymph nodes (LNs) sampled by endoscopic ultrasound fine-needle aspiration (EUS FNA) of patients with rectal cancer by targeted next-generation sequencing (NGS).
METHODS: The NGS Ion AmpliSeq Cancer Hotspot Panel v2 (Life Technologies, Carlsbad, CA) and MiSeq (Illumina, San Diego, CA) sequencers were used to sequence and assess for 2,800 or more possible mutations in 50 established cancer-associated genes.
RESULTS: Among 102 patients, 89% had 194 pathogenic alterations identified in 19 genes. The identification of KRAS, NRAS, or BRAF mutations suggests that 42% are likely nonresponders to anti-epidermal growth factor receptor therapy. Among KRAS, NRAS, or BRAF wild-type patients, alterations in eight genes linked to alternative therapies were identified in 44%.
CONCLUSIONS: Our data demonstrate the successful ability to apply a single multiplex test to allow multigene mutation detection from malignant LN cytology specimen DNA collected by EUS FNA.

Sato S, Motoi N, Hiramatsu M, et al.
Pulmonary adenocarcinoma in situ: analyses of a large series with reference to smoking, driver mutations, and receptor tyrosine kinase pathway activation.
Am J Surg Pathol. 2015; 39(7):912-21 [PubMed] Related Publications
Lung adenocarcinomas in situ (AISs) often occur in individuals who have never smoked, although smoking is one of the main causes of lung cancer. To characterize AIS and, in particular, determine how AIS might be related to smoking, we collected a large number of AIS cases and examined clinicopathologic features, EGFR and KRAS mutation status, and activation status of receptor tyrosine kinase downstream signal pathways, including pAkt, pERK, and pStat3, using immunohistochemistry. We identified 110 AISs (36 smokers and 74 nonsmokers) among 1549 adenocarcinomas resected surgically during 1995 to 2010. Between the AIS of smokers and nonsmokers, only the sex ratio was significantly different; all the other clinicopathologic factors including TTF-1 and driver mutations were not significantly different: EGFR and KRAS mutation rates (smokers:nonsmokers) were 61:58 (%) (P=0.7) and 6.1:1.4 (%) (P=0.2), respectively, whereas, in invasive adenocarcinomas, the rates were 41:69 (%) (P<0.001) and 9.4:2.3 (%) (P<0.04), respectively. For pAkt and pERK, around 40% to 50% of AISs were positive, and for pStat3, >80% were positive, with no significant differences between smokers and nonsmokers with AIS. Mucinous AIS (n=8) rarely harbored KRAS mutations and expressed significantly less pStat3 (P<0.001) than nonmucinous AIS. Taken together, AIS occurs predominantly in female individuals and nonsmokers. However, characteristics of AIS arising in smokers and nonsmokers were similar in terms of cell lineage, driver mutations, and receptor tyrosine kinase pathway activation. Our results suggest that smoking is not a major cause of AIS. Rather, smoking may play a role in progression of AIS to invasive adenocarcinoma with AIS features.

Scudellari M
Drug development: Mix and match.
Nature. 2015; 521(7551):S12-4 [PubMed] Related Publications

Azzato EM, Deshpande C, Aikawa V, et al.
Rare Complex Mutational Profile in an ALK Inhibitor-resistant Non-small Cell Lung Cancer.
Anticancer Res. 2015; 35(5):3007-12 [PubMed] Related Publications
Testing for somatic alterations, including anaplastic lymphoma receptor tyrosine kinase gene (ALK) rearrangements and epidermal growth factor receptor gene (EGFR) mutations, is standard practice in the diagnostic evaluation and therapeutic management of non-small cell lung cancer (NSCLC), where the results of such tests can predict response to targeted-therapy. ALK rearrangements, EGFR mutations and mutations in the Kirsten rat sarcoma viral oncogene homolog (KRAS) are considered mutually exclusive in NSCLC. Herein we identified a KRAS Q22K mutation and frameshift mutations in the genes encoding serine/threonine kinase 11 (STK11) and ataxia telangiectasia mutated serine/threonine kinase (ATM) by next-generation sequencing in a patient with ALK rearrangement-positive oligo-metastatic NSCLC, whose disease progressed while on two ALK-targeted therapies. Such a complex diagnostic genetic profile has not been reported in ALK fusion-positive NSCLC. This case highlights the utility of comprehensive molecular testing in the diagnosis of NSCLC.

Amankwatia EB, Chakravarty P, Carey FA, et al.
MicroRNA-224 is associated with colorectal cancer progression and response to 5-fluorouracil-based chemotherapy by KRAS-dependent and -independent mechanisms.
Br J Cancer. 2015; 112(9):1480-90 [PubMed] Article available free on PMC after 28/04/2016 Related Publications
BACKGROUND: Colorectal cancers arise from benign adenomas, although not all adenomas progress to cancer and there are marked interpatient differences in disease progression. We have previously associated KRAS mutations with disease progression and reduced survival in colorectal cancer patients.
METHODS: We used TaqMan low-density array (TLDA) qRT-PCR analysis to identify miRNAs differentially expressed in normal colorectal mucosa, adenomas and cancers and in isogeneic KRAS WT and mutant HCT116 cells, and used a variety of phenotypic assays to assess the influence of miRNA expression on KRAS activity, chemosensitivity, proliferation and invasion.
RESULTS: MicroRNA-224 was differentially expressed in dysplastic colorectal disease and in isogeneic KRAS WT and mutant HCT116 cells. Antagomir-mediated miR-224 silencing in HCT116 KRAS WT cells phenocopied KRAS mutation, increased KRAS activity and ERK and AKT phosphorylation. 5-FU chemosensitivity was significantly increased in miR-224 knockdown cells, and in NIH3T3 cells expressing KRAS and BRAF mutant proteins. Bioinformatics analysis of predicted miR-224 target genes predicted altered cell proliferation, invasion and epithelial-mesenchymal transition (EMT) phenotypes that were experimentally confirmed in miR-224 knockdown cells.
CONCLUSIONS: We describe a novel mechanism of KRAS regulation, and highlight the clinical utility of colorectal cancer-specific miRNAs as disease progression or clinical response biomarkers.

Dienstmann R, Salazar R, Tabernero J
Personalizing colon cancer adjuvant therapy: selecting optimal treatments for individual patients.
J Clin Oncol. 2015; 33(16):1787-96 [PubMed] Related Publications
For more than three decades, postoperative chemotherapy-initially fluoropyrimidines and more recently combinations with oxaliplatin-has reduced the risk of tumor recurrence and improved survival for patients with resected colon cancer. Although universally recommended for patients with stage III disease, there is no consensus about the survival benefit of postoperative chemotherapy in stage II colon cancer. The most recent adjuvant clinical trials have not shown any value for adding targeted agents, namely bevacizumab and cetuximab, to standard chemotherapies in stage III disease, despite improved outcomes in the metastatic setting. However, biomarker analyses of multiple studies strongly support the feasibility of refining risk stratification in colon cancer by factoring in molecular characteristics with pathologic tumor staging. In stage II disease, for example, microsatellite instability supports observation after surgery. Furthermore, the value of BRAF or KRAS mutations as additional risk factors in stage III disease is greater when microsatellite status and tumor location are taken into account. Validated predictive markers of adjuvant chemotherapy benefit for stage II or III colon cancer are lacking, but intensive research is ongoing. Recent advances in understanding the biologic hallmarks and drivers of early-stage disease as well as the micrometastatic environment are expected to translate into therapeutic strategies tailored to select patients. This review focuses on the pathologic, molecular, and gene expression characterizations of early-stage colon cancer; new insights into prognostication; and emerging predictive biomarkers that could ultimately help define the optimal adjuvant treatments for patients in routine clinical practice.

Singh N, Sahu DK, Goel M, et al.
Retrospective analysis of FFPE based Wilms' Tumor samples through copy number and somatic mutation related Molecular Inversion Probe Based Array.
Gene. 2015; 565(2):295-308 [PubMed] Related Publications
In this report, retrospectively, we analyzed fifteen histo-pathologically characterized FFPE based Wilms' Tumor (WT) samples following an integrative approach of copy number (CN) and loss of heterozygosity (LOH) imbalances. The isolated-DNA was tested on CN and somatic-mutation related Molecular-Inversion-Probe based-Oncoscan Array™ and was analyzed through Nexus-Express OncoScan-3.0 and 7.0 software. We identified gain of 3p13.0-q29, 4p16.3-14.0, 7, 12p13.33-q24.33, and losses of 1p36.11-q44, 11p15.5-q25, 21q 22.2-22.3 and 22q11.21-13.2 in six samples (W1-6) and validated them in nine more samples (W7-9, W12-15, W17-18). Some observed that discrete deletions (1p, 1q, 10p, 10q, 13q, 20p) were specific to our samples. Maximum-LOH was observed in Ch11 as reported in previous studies. However, LOH was also observed in different regions of Ch7 including some cancer genes. The identified LOH-regions (1q21.2-q21.3, 2p24.1-23.3, 2p24.3-24.3, 3p21.3-21.1, 4p16.3, 7p11.2-p11.1, 7q31.2-31.32, 7q34-q35 and Ch 8) in W1-W6 were also validated in W7-9, W12-15 and W18. In addition, previously reported LOH of 1p and 16q region was also observed in our cases. The proven and novel onco (OG)- and tumor-suppressor genes (TSGs) involved in the CNV regions affected the major pathways like Chromatin Modification, RAS, PI3K; RAS in 14/15 cases, NOTCH/TGF-β and Cell Cycle Apoptosis in 10/15 cases, APC in 9/15 cases and Transcriptional Regulation in 7/15 cases, PI3K and genome maintenance in 6/15 cases. This exhaustive profiling of OG and TG may help in prognosis and diagnosis of the disease after validation of all the relevant results, especially the novel ones, obtained in this research in a larger number of samples.

Miyasaka A, Oda K, Ikeda Y, et al.
PI3K/mTOR pathway inhibition overcomes radioresistance via suppression of the HIF1-α/VEGF pathway in endometrial cancer.
Gynecol Oncol. 2015; 138(1):174-80 [PubMed] Related Publications
Radiation therapy is a key therapeutic strategy for endometrial carcinomas. However, biomarkers that predict radiosensitivity and drugs to enhance this sensitivity have not yet been established. We aimed to investigate the roles of TP53 and MAPK/PI3K pathways in endometrial carcinomas and to identify appropriate radiosensitizing therapeutics. D10 values (the irradiating dose required to reduce a cell population by 90%) were determined in eight endometrial cancer cell lines with known mutational statuses for TP53, PIK3CA, and KRAS. Cells were exposed to ionizing radiation (2-6Gy) and either a dual PI3K/mTOR inhibitor (NVP-BEZ235) or a MEK inhibitor (UO126), and their radiosensitizing effects were evaluated using clonogenic assays. The effects of silencing hypoxia-inducible factor-1 α (HIF-1α) expression with small interfering RNAs (siRNAs) were evaluated following exposure to ionizing radiation (2-3Gy). D10 values ranged from 2.0 to 3.1Gy in three cell lines expressing wild-type TP53 or from 3.3 to more than 6.0Gy in five cell lines expressing mutant TP53. NVP-BEZ235, but not UO126, significantly improved radiosensitivity through the suppression of HIF-1α/vascular endothelial growth factor-A expression. HIF-1α silencing significantly increased the induction of the sub-G1 population by ionizing radiation. Our study data suggest that TP53 mutation and PI3K pathway activation enhances radioresistance in endometrial carcinomas and that targeting the PI3K/mTOR or HIF-1α pathways could improve radiosensitivity.

Rui Y, Wang C, Zhou Z, et al.
K-Ras mutation and prognosis of colorectal cancer: a meta-analysis.
Hepatogastroenterology. 2015 Jan-Feb; 62(137):19-24 [PubMed] Related Publications
BACKGROUND/AIMS: Colorectal cancer (CRC) is one of the most common malignant tumors worldwide. Kirsten ras (K-ras) gene is considered to participate in the progression from adenoma to carcinoma of colorectal neoplasms. The correlation between K-ras mutation and the prognosis of CRC is sill controversial. This study aimed at quantitatively summarizing the evidence for such a relationship.
METHODOLOGY: The literature search was based on Pub Med. Population-based and hospital-based case-control studies concerning K-ras mutation and prognosis were eligible for analysis.
RESULTS: 13 literatures were included in the meta-analysis, with 1 multicenter study and 12 case control studies. Totally, 3771 patients were enrolled in the analysis, 1202 of which had K-ras mutation. There were significant difference between the survival of patients with normal and mutated K-ras gene, but no statistic differences were found between either Condon 12 or Condon 13 mutations and prognosis.
CONCLUSION: Current available evidences demonstrated the K-ras mutation is a predictive molecular mark of colorectal cancer patients' survivals, further studies are needed to investigate the race difference and the relationship between certain K-ras mutation and prognosis.

Asl JM, Almasi S, Tabatabaiefar MA
High frequency of BRAF proto-oncogene hot spot mutation V600E in cohort of colorectal cancer patients from Ahvaz City, southwest Iran.
Pak J Biol Sci. 2014; 17(4):565-9 [PubMed] Related Publications
Colorectal cancer (CRC) is one of the most common forms of cancer around the world. Sporadic CRCs are caused by accumulation of mutations in essential genes regulating normal proliferation and differentiation of cells. The proto-oncogene BRAF encoded by the BRAF gene is involved in the RAS/RAF/MAPK pathway of signal transduction during cell growth. Acquired mutations in BRAF have been found at high frequencies in adult patients with papillary thyroid carcinoma and sporadic CRC. One of the predominant hot spot point mutations is T1799A (V600E) mutation among a cohort of CRC patients from Ahvaz city, southwest Iran. The aim of this study was to estimate the frequency of V600E mutation in CRC patients from Ahvaz city, southwest Iran. We analyzed exon 15 of the BRAF gene in isolated DNA from 80 Formalin Fixed Paraffin-embedded (FFPE) CRC tumor tissues using PCR-RFLP method. Data were analyzed using SPSS statistical program. According to our results 37 out of 80 cases (46.25%) were heterozygous for the mutation while the remaining 43 cases (53.75%) had normal homozygous genotype. No homozygous mutant genotype was found. Based on our findings, the frequency of V600E mutation appears to be significantly increased among CRC patients of the studied population but there was no significant relationship between genotypes and age and sex. In conclusion, these findings might prove the effect of V600E mutation on CRC pathogenesis. However, the exact effect of the mutation in CRC progression requires further work.

Pollizzi KN, Patel CH, Sun IH, et al.
mTORC1 and mTORC2 selectively regulate CD8⁺ T cell differentiation.
J Clin Invest. 2015; 125(5):2090-108 [PubMed] Article available free on PMC after 28/04/2016 Related Publications
Activation of mTOR-dependent pathways regulates the specification and differentiation of CD4+ T effector cell subsets. Herein, we show that mTOR complex 1 (mTORC1) and mTORC2 have distinct roles in the generation of CD8+ T cell effector and memory populations. Evaluation of mice with a T cell-specific deletion of the gene encoding the negative regulator of mTORC1, tuberous sclerosis complex 2 (TSC2), resulted in the generation of highly glycolytic and potent effector CD8+ T cells; however, due to constitutive mTORC1 activation, these cells retained a terminally differentiated effector phenotype and were incapable of transitioning into a memory state. In contrast, CD8+ T cells deficient in mTORC1 activity due to loss of RAS homolog enriched in brain (RHEB) failed to differentiate into effector cells but retained memory characteristics, such as surface marker expression, a lower metabolic rate, and increased longevity. However, these RHEB-deficient memory-like T cells failed to generate recall responses as the result of metabolic defects. While mTORC1 influenced CD8+ T cell effector responses, mTORC2 activity regulated CD8+ T cell memory. mTORC2 inhibition resulted in metabolic reprogramming, which enhanced the generation of CD8+ memory cells. Overall, these results define specific roles for mTORC1 and mTORC2 that link metabolism and CD8+ T cell effector and memory generation and suggest that these functions have the potential to be targeted for enhancing vaccine efficacy and antitumor immunity.

Slattery ML, Herrick JS, Mullany LE, et al.
Improved survival among colon cancer patients with increased differentially expressed pathways.
BMC Med. 2015; 13:75 [PubMed] Article available free on PMC after 28/04/2016 Related Publications
BACKGROUND: Studies of colorectal cancer (CRC) have shown that hundreds to thousands of genes are differentially expressed in tumors when compared to normal tissue samples. In this study, we evaluate how genes that are differentially expressed in colon versus normal tissue influence survival.
METHODS: We performed RNA-seq on tumor/normal paired samples from 175 colon cancer patients. We implemented a cross validation strategy to determine genes that were significantly differentially expressed between tumor and normal samples. Differentially expressed genes were evaluated with Ingenuity Pathway Analysis to identify key pathways that were de-regulated. A summary differential pathway expression score (DPES) was developed to summarize hazard of dying while adjusting for age, American Joint Committee on Cancer (AJCC) stage, sex, and tumor molecular phenotype, i.e., MSI, TP53, KRAS, and CIMP.
RESULTS: A total of 1,138 genes were up-regulated and 695 were down-regulated. These de-regulated genes were enriched for 19 Ingenuity Canonical Pathways, with the most significant pathways involving cell signaling and growth. Of the enriched pathways, 16 were significantly associated with CRC-specific mortality, including 1 metabolic pathway and 15 signaling pathways. In all instances, having a higher DPES (i.e., more de-regulated genes) was associated with better survival. Further assessment showed that individuals diagnosed at AJCC Stage 1 had more de-regulated genes than individuals diagnosed at AJCC Stage 4.
CONCLUSIONS: Our data suggest that having more de-regulated pathways is associated with a good prognosis and may be a reaction to key events that are disabling to tumor progression. Please see related article: .

Ratner N, Miller SJ
A RASopathy gene commonly mutated in cancer: the neurofibromatosis type 1 tumour suppressor.
Nat Rev Cancer. 2015; 15(5):290-301 [PubMed] Related Publications
Neurofibromatosis type 1 (NF1) is a common genetic disorder that predisposes affected individuals to tumours. The NF1 gene encodes a RAS GTPase-activating protein called neurofibromin and is one of several genes that (when mutant) affect RAS-MAPK signalling, causing related diseases collectively known as RASopathies. Several RASopathies, beyond NF1, are cancer predisposition syndromes. Somatic NF1 mutations also occur in 5-10% of human sporadic cancers and may contribute to resistance to therapy. To highlight areas for investigation in RASopathies and sporadic tumours with NF1 mutations, we summarize current knowledge of NF1 disease, the NF1 gene and neurofibromin, neurofibromin signalling pathways and recent developments in NF1 therapeutics.

Larsen CJ
[In vivo "editing'' of cellular genome: one more step toward animals models mimicking tumorigenesis].
Bull Cancer. 2015; 102(2):114-5 [PubMed] Related Publications

Wu H, Gao L, Li F, et al.
Identifying overlapping mutated driver pathways by constructing gene networks in cancer.
BMC Bioinformatics. 2015; 16 Suppl 5:S3 [PubMed] Article available free on PMC after 28/04/2016 Related Publications
BACKGROUND: Large-scale cancer genomic projects are providing lots of data on genomic, epigenomic and gene expression aberrations in many cancer types. One key challenge is to detect functional driver pathways and to filter out nonfunctional passenger genes in cancer genomics. Vandin et al. introduced the Maximum Weight Sub-matrix Problem to find driver pathways and showed that it is an NP-hard problem.
METHODS: To find a better solution and solve the problem more efficiently, we present a network-based method (NBM) to detect overlapping driver pathways automatically. This algorithm can directly find driver pathways or gene sets de novo from somatic mutation data utilizing two combinatorial properties, high coverage and high exclusivity, without any prior information. We firstly construct gene networks based on the approximate exclusivity between each pair of genes using somatic mutation data from many cancer patients. Secondly, we present a new greedy strategy to add or remove genes for obtaining overlapping gene sets with driver mutations according to the properties of high exclusivity and high coverage.
RESULTS: To assess the efficiency of the proposed NBM, we apply the method on simulated data and compare results obtained from the NBM, RME, Dendrix and Multi-Dendrix. NBM obtains optimal results in less than nine seconds on a conventional computer and the time complexity is much less than the three other methods. To further verify the performance of NBM, we apply the method to analyze somatic mutation data from five real biological data sets such as the mutation profiles of 90 glioblastoma tumor samples and 163 lung carcinoma samples. NBM detects groups of genes which overlap with known pathways, including P53, RB and RTK/RAS/PI(3)K signaling pathways. New gene sets with p-value less than 1e-3 are found from the somatic mutation data.
CONCLUSIONS: NBM can detect more biologically relevant gene sets. Results show that NBM outperforms other algorithms for detecting driver pathways or gene sets. Further research will be conducted with the use of novel machine learning techniques.

Satoh K
[The molecular mechanism of the invasion and metastasis in the pancreatic ductal adenocarcinoma].
Nihon Rinsho. 2015; 73 Suppl 3:16-21 [PubMed] Related Publications

Dang J, Wei L, de Ridder J, et al.
PAX5 is a tumor suppressor in mouse mutagenesis models of acute lymphoblastic leukemia.
Blood. 2015; 125(23):3609-17 [PubMed] Article available free on PMC after 04/06/2016 Related Publications
Alterations of genes encoding transcriptional regulators of lymphoid development are a hallmark of B-progenitor acute lymphoblastic leukemia (B-ALL) and most commonly involve PAX5, encoding the DNA-binding transcription factor paired-box 5. The majority of PAX5 alterations in ALL are heterozygous, and key PAX5 target genes are expressed in leukemic cells, suggesting that PAX5 may be a haploinsufficient tumor suppressor. To examine the role of PAX5 alterations in leukemogenesis, we performed mutagenesis screens of mice heterozygous for a loss-of-function Pax5 allele. Both chemical and retroviral mutagenesis resulted in a significantly increased penetrance and reduced latency of leukemia, with a shift to B-lymphoid lineage. Genomic profiling identified a high frequency of secondary genomic mutations, deletions, and retroviral insertions targeting B-lymphoid development, including Pax5, and additional genes and pathways mutated in ALL, including tumor suppressors, Ras, and Janus kinase-signal transducer and activator of transcription signaling. These results show that in contrast to simple Pax5 haploinsufficiency, multiple sequential alterations targeting lymphoid development are central to leukemogenesis and contribute to the arrest in lymphoid maturation characteristic of ALL. This cross-species analysis also validates the importance of concomitant alterations of multiple cellular growth, signaling, and tumor suppression pathways in the pathogenesis of B-ALL.

Mit'kevich VA, Makarov AA, Il'inskaia ON
[Cellular targets of antitumor ribonucleases].
Mol Biol (Mosk). 2014 Mar-Apr; 48(2):214-22 [PubMed] Related Publications
Some ribonucleases (RNases) produce selective toxic effect on the cancer cells. The mechanism of this antitumor activity remains largely unclear. The subject of this review is the RNases interaction with cellular components, resulting in the induction of apoptosis of tumor cells. Cell surface structures, which are potential acceptors of the exogenous RNase are discussed: acidic lipids and glycoproteins, heparansulfate-containing proteoglycans, actin, and RNA-associated proteins. Cell membranes of normal and malignant cells differ according to the composition of these components, which largely determines the selectivity of RNases for the latter. Different types of RNA are examined as intracellular targets of the RNases activity, evidence is presented demonstrating the possibility of exogenous RNases intervening in the process of RNA interference. The role of potassium channels, NF-kappaB-dependent.signaling pathway and various caspases in apoptosis induced by exogenous RNases is discussed. Evidence is also presented showing that the sensitivity of cells to exogenous RNases is linked to the expression of certain oncogenes, namely RAS, KIT, AML1-ETO. It is suggested that discovering the details of the mechanisms of RNases cytotoxic effect in malignant cells susceptible to their activity, will in the future serve as a foundation to developing new tools of targeted anticancer therapy.

Doma V, Gulya E
[Genetic diversity and immunological characteristics of malignant melanoma: the therapeutic spectrum].
Orv Hetil. 2015; 156(15):583-91 [PubMed] Related Publications
Malignant melanoma, originating from pigment cells, is a highly aggressive tumour affecting patients of any age group. Its incidence is rapidly growing. The most common form can be easily diagnosed by any physician. There are some well-known genetic (skin-, eye-, hair colour, naevi, melanoma in the personal/family history) and environmental (ultraviolet radiation) predisposing factors. Treatment is based on early diagnosis and excision. When metastasis occurs, the traditional chemo- and radiotherapy gives a low response rate. Recently some newly approved targeted therapies and immunomodulant drugs have become available. This review focuses on the classification and novel therapeutic approaches of malignant melanoma to provide guidance to clinicians.

Galliani CA, Sanchez IC, D'Errico MM, Bisceglia M
Selected case from the Arkadi M. Rywlin International Pathology Slide Club: carcinoma of the transverse colon in a young girl.
Adv Anat Pathol. 2015; 22(3):217-24 [PubMed] Related Publications
We report a case of a 14-year-old female with primary adenocarcinoma of the transverse colon. She was hospitalized after presenting with abdominal pain and signs of intestinal obstruction. There was no health antecedent or family history of neoplasia. Physical examination revealed a distended abdomen. Tenderness was elicited to palpation of the right lower quadrant. Magnetic resonance imaging of the abdomen revealed obstructive signs, with a constricting lesion in the mid-transverse colon of probable neoplastic nature. Laparoscopic segmental resection of the colon was followed by standard right hemicolectomy. A circumferential mid-transverse tumor was diagnosed as primary colorectal carcinoma (CRC) of signet-ring cell type, AJCC stage IIIC, Dukes' C stage. On the basis of immunohistochemistry and clinical data, hereditary nonpolyposis and hamartomatous colorectal cancer syndromes were excluded. Involvement of either the p53, BRAF, or K-RAS genes was ruled out by immunohistochemistry profiling and genetic testing. The neoplasm was categorized as sporadic. The possibility of activation of the Wnt signaling pathway was suspected, because of a defective turnover of the β-catenin protein. Postoperatively, the patient was treated with both systemic and intra-abdominal adjuvant chemotherapy, including oxaliplatin. Between 18 and 24 months after diagnosis, intra-abdominal tumor recurrences were detected. The patient underwent bilateral oophorectomies for Krukenberg tumors and received salvage chemotherapy. Recently, additional recurrent metastatic retroperitoneal disease caused hydronephrosis. The retroperitoneal mass was debulked and a ureteric stent was placed. At the time of this writing, 43 months after diagnosis, the patient is receiving FOLFOX chemotherapy combined with panitumumab. CRC of childhood is exceedingly rare, generally develops in the setting of unrecognized genetic predisposing factors to cancer, presents with advanced disease, is high grade, and tends to have dismal prognosis.

Califano R, Abidin A, Tariq NU, et al.
Beyond EGFR and ALK inhibition: unravelling and exploiting novel genetic alterations in advanced non small-cell lung cancer.
Cancer Treat Rev. 2015; 41(5):401-11 [PubMed] Related Publications
During the last decade, thoracic oncology has witnessed an unprecedented outburst of knowledge regarding molecular biology of non small-cell lung cancer (NSCLC). The implementation of high-throughput sequencing analysis and genomic technologies has led to the identification of novel molecular events that characterize NSCLC transformation and may represent critical oncogenic drivers amenable to targeted therapy. Among these, the presence of activating mutations of the epidermal growth factor receptor (EGFR) gene and of chromosomic rearrangements in the anaplastic-lymphoma kinase (ALK) proto-oncogene, have been the first well characterized genetic alterations with corresponding targeted agents to enter the clinical arena. Nevertheless, in the recent years a number of other oncogenic drivers beyond EGFR and ALK inhibition have emerged as novel molecular targets with potential therapeutic implications, including mutations in the genes KRAS, BRAF, HER2, PI3KCA and DDR2, as well as ROS1 and RET rearrangements and MET, HER2 and FGFR1 gene amplifications. The aim of this review is to provide comprehensive information on the novel therapeutic targets identified by recent preclinical evidence and to discuss developments in molecular treatments targeting these oncogenic drivers or actionable mutations beyond EGFR and ALK in advanced NSCLC.

Tan MC, Basturk O, Brannon AR, et al.
GNAS and KRAS Mutations Define Separate Progression Pathways in Intraductal Papillary Mucinous Neoplasm-Associated Carcinoma.
J Am Coll Surg. 2015; 220(5):845-54.e1 [PubMed] Article available free on PMC after 01/05/2016 Related Publications
BACKGROUND: Intraductal papillary mucinous neoplasms (IPMN) are being increasingly recognized as important precursors to pancreatic adenocarcinoma. Elucidation of the genetic changes underlying IPMN carcinogenesis may improve the diagnosis and management of IPMN. We sought to determine whether different histologic subtypes of IPMN would exhibit different frequencies of specific genetic mutations.
STUDY DESIGN: Patients with resected IPMN-associated invasive carcinoma (IPMN-INV) between 1997 and 2012 were reviewed. Areas of carcinoma, high-grade dysplasia, and low-grade dysplasia were micro-dissected from each pathologic specimen. Targeted, massively parallel sequencing was then performed on a panel of 275 genes (including KRAS, GNAS, and RNF43).
RESULTS: Thirty-eight patients with resected IPMN-INV and sufficient tissue for micro-dissection were identified. Median follow-up was 2.6 years. Mutations in GNAS were more prevalent in colloid-type IPMN-INV than tubular-type IPMN-INV (89% vs 32% respectively; p = 0.0003). Conversely, KRAS mutations were more prevalent in tubular-type than colloid-type IPMN-INV (89% vs 52%, respectively; p = 0.01). For noninvasive IPMN subtypes, GNAS mutations were more prevalent in intestinal (74%) compared with pancreatobiliary (31%) and gastric (50%) subtypes (p = 0.02). The presence of these mutations did not vary according to the degree of dysplasia (GNAS: invasive 61%, high-grade 59%, low-grade 53%; KRAS: invasive 71%, high-grade 62%, low-grade 74%), suggesting that mutations in these genes occur early in IPMN carcinogenesis.
CONCLUSIONS: Colloid carcinoma associated with IPMN and its intestinal-type preinvasive precursor are associated with high frequencies of GNAS mutations. The mutation profile of tubular carcinoma resembles that of conventional pancreatic adenocarcinoma. Preoperative determination of mutational status may assist with clinical treatment decisions.

de Macêdo MP, de Melo FM, Lisboa BC, et al.
KRAS gene mutation in a series of unselected colorectal carcinoma patients with prognostic morphological correlations: a pyrosequencing method improved by nested PCR.
Exp Mol Pathol. 2015; 98(3):563-7 [PubMed] Related Publications
INTRODUCTION: Inhibition of EGFR is a strategy for treating metastatic colorectal cancer (CRC) patients. KRAS sequencing is mandatory for selecting wild-type tumor patients who might benefit from this treatment. DNA from formalin-fixed paraffin-embedded (FFPE) tissues is commonly used for routine clinical detection of mutations, and its amplification succeeds only when all preanalytical histological processes have been controlled. In cases that are not properly processed, the DNA results can be poor, with low peak pyrosequencing findings. We designed and tested a pair of forward and reverse primers for a nested PCR method, followed by pyrosequencing, in a single Latin American institution series of 422 unselected CRC patients, correlating KRAS mutations with pathological and clinical data.
MATERIALS AND METHODS: Patient DNA samples from tumors were obtained by scraping or laser microdissection of cells from FFPE tissue and extracted using a commercial kit. DNA was first amplified by PCR using 2 primers that we designed; then, nested PCR was performed with the amplicon from the preamplification PCR using the KRAS PyroMark™ Q96 V2.0 kit (Qiagen). Pathological data were retrieved from pathology reports.
RESULTS: KRAS mutation was observed in 33% of 421 cases. Codon 12 was mutated in 76% of cases versus codon 13 in 24%. Right-sided CRCs harbored more KRAS mutations than left-sided tumors, as did tumors that presented with perineural invasion.
CONCLUSION: Our findings in this Latin American population are consistent with the literature regarding the frequency of KRAS mutations in CRC, their distribution between codons 12 and 13, and type of nucleotide substitution. By combining nested PCR and pyrosequencing, we achieved a high rate of conclusive results in testing KRAS mutations in CRC samples - a method that can be used as an ancillary test for failed assays by conventional PCR.

Zhao Z, Chen CC, Rillahan CD, et al.
Cooperative loss of RAS feedback regulation drives myeloid leukemogenesis.
Nat Genet. 2015; 47(5):539-43 [PubMed] Article available free on PMC after 01/11/2015 Related Publications
RAS network activation is common in human cancers, and in acute myeloid leukemia (AML) this activation is achieved mainly through gain-of-function mutations in KRAS, NRAS or the receptor tyrosine kinase FLT3. We show that in mice, premalignant myeloid cells harboring a Kras(G12D) allele retained low levels of Ras signaling owing to negative feedback involving Spry4 that prevented transformation. In humans, SPRY4 is located on chromosome 5q, a region affected by large heterozygous deletions that are associated with aggressive disease in which gain-of-function mutations in the RAS pathway are rare. These 5q deletions often co-occur with chromosome 17 alterations involving the deletion of NF1 (another RAS negative regulator) and TP53. Accordingly, combined suppression of Spry4, Nf1 and p53 produces high levels of Ras signaling and drives AML in mice. Thus, SPRY4 is a tumor suppressor at 5q whose disruption contributes to a lethal AML subtype that appears to acquire RAS pathway activation through a loss of negative regulators.

Viala M, Brosseau S, Planchard D, et al.
[Second generation ALK inhibitors in non-small cell lung cancer: systemic review].
Bull Cancer. 2015; 102(4):381-9 [PubMed] Related Publications
The identification of the EML4-ALK rearrangement in 5% of NSCLC enhanced the development of 1st generation ALK inhibitors such as crizotinib. Two phase III trials demonstrated crizotinib efficacy in second line metastatic (PROFILE 1007) and more recently first line metastatic (PROFILE 1014) NSCLC in terms of progression-free survival and also objective response. However, within 12 to 16 months, patients will progress due to the emergence of acquired resistance mechanisms such as mutation (L1196M) or amplification of the ALK gene, as well as activation of alternative signaling pathways (EGFR, KRAS). Second generation ALK inhibitors have been developed such as ceritinib, alectinib, and AP26113. This review will present those new drugs, summarize the results of their ongoing trials, and discuss the best way to treat ALK+ NSCLC patients.

Dang M, Zon LI
Screening for melanoma resistance genes in vivo.
Pigment Cell Melanoma Res. 2015; 28(4):375-6 [PubMed] Related Publications

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