HLA-G

Gene Summary

Gene:HLA-G; major histocompatibility complex, class I, G
Aliases: MHC-G
Location:6p21.3
Summary:HLA-G belongs to the HLA class I heavy chain paralogues. This class I molecule is a heterodimer consisting of a heavy chain and a light chain (beta-2 microglobulin). The heavy chain is anchored in the membrane. HLA-G is expressed on fetal derived placental cells. The heavy chain is approximately 45 kDa and its gene contains 8 exons. Exon one encodes the leader peptide, exons 2 and 3 encode the alpha1 and alpha2 domain, which both bind the peptide, exon 4 encodes the alpha3 domain, exon 5 encodes the transmembrane region, and exon 6 encodes the cytoplasmic tail. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:HLA class I histocompatibility antigen, alpha chain G
HPRD
Source:NCBIAccessed: 11 August, 2015

Ontology:

What does this gene/protein do?
Show (27)
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.

  • Receptors, Immunologic
  • Solubility
  • Thyroid Cancer
  • Tumor Markers
  • Tunisia
  • Tissue Array Analysis
  • B-Cell Lymphoma
  • RTPCR
  • Major Histocompatibility Complex
  • Young Adult
  • Transcription
  • Genotype
  • Risk Factors
  • Natural Killer Cells
  • Reed-Sternberg Cells
  • Polymorphism
  • T-Lymphocytes
  • Bladder Cancer
  • Messenger RNA
  • Case-Control Studies
  • Chromosome 6
  • Tumor Burden
  • V-Set Domain-Containing T-Cell Activation Inhibitor 1
  • Breast Cancer
  • HLA Antigens
  • Gene Expression
  • Transcriptional Activation
  • Cancer Gene Expression Regulation
  • Cervical Cancer
  • Tumor Escape
  • Flow Cytometry
  • Republic of Korea
  • Vaginal Cancer
  • Stomach Cancer
  • Reproduction
  • Smoking
  • HLA-G Antigens
  • Staging
  • Histocompatibility Antigens Class I
  • Genetic Predisposition
Tag cloud generated 11 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (7)

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

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

Latest Publications: HLA-G (cancer-related)

Wang Y, Fan X, Li H, et al.
Tumor border sharpness correlates with HLA-G expression in low-grade gliomas.
J Neuroimmunol. 2015; 282:1-6 [PubMed] Related Publications
Human leukocyte antigen-G (HLA-G) is a tumor microenvironment molecule that is involved in the escape of cancerous tumors from host immune recognition and destruction. This study investigated the potential relationship between HLA-G expression levels and the sharpness of low-grade glioma tumor borders in magnetic resonance images. Preoperative T2-weighted images from 72 patients were retrospectively examined by manually segmenting the hyperintensive tumor areas and subsequently registering them to a standard brain template. Then, the intensity of the voxels inside the tumor border (tumor voxels) was compared with that of the voxels outside the tumor border (paratumor voxels). The radiologic sharpness of a tumor was defined as the mean ratio of the intensity of the tumor voxels to the intensity of the paratumor voxels. Tumors with high HLA-G expression were associated with larger tumors and lower mean hyperintensive contrast. These findings suggest that tumors with blurred boundaries may be those prone to diffuse invasion. Additionally, patients with tumors having high HLA-G expression were less likely to have undergone complete resections. Thus, this study is the first to identify an association between HLA-G expression and the radiologic morphology of the tumor border, and may further our understanding of the role of the HLA gene in immune escape in patients with low-grade gliomas.

Yang Y, Adachi K, Sheridan MA, et al.
Heightened potency of human pluripotent stem cell lines created by transient BMP4 exposure.
Proc Natl Acad Sci U S A. 2015; 112(18):E2337-46 [PubMed] Free Access to Full Article Related Publications
Human pluripotent stem cells (PSCs) show epiblast-type pluripotency that is maintained with ACTIVIN/FGF2 signaling. Here, we report the acquisition of a unique stem cell phenotype by both human ES cells (hESCs) and induced pluripotent stem cells (iPSCs) in response to transient (24-36 h) exposure to bone morphogenetic protein 4 (BMP4) plus inhibitors of ACTIVIN signaling (A83-01) and FGF2 (PD173074), followed by trypsin dissociation and recovery of colonies capable of growing on a gelatin substratum in standard medium for human PSCs at low but not high FGF2 concentrations. The self-renewing cell lines stain weakly for CDX2 and strongly for NANOG, can be propagated clonally on either Matrigel or gelatin, and are morphologically distinct from human PSC progenitors on either substratum but still meet standard in vitro criteria for pluripotency. They form well-differentiated teratomas in immune-compromised mice that secrete human chorionic gonadotropin (hCG) into the host mouse and include small areas of trophoblast-like cells. The cells have a distinct transcriptome profile from the human PSCs from which they were derived (including higher expression of NANOG, LEFTY1, and LEFTY2). In nonconditioned medium lacking FGF2, the colonies spontaneously differentiated along multiple lineages, including trophoblast. They responded to PD173074 in the absence of both FGF2 and BMP4 by conversion to trophoblast, and especially syncytiotrophoblast, whereas an A83-01/PD173074 combination favored increased expression of HLA-G, a marker of extravillous trophoblast. Together, these data suggest that the cell lines exhibit totipotent potential and that BMP4 can prime human PSCs to a self-renewing alternative state permissive for trophoblast development. The results may have implications for regulation of lineage decisions in the early embryo.

Guo ZY, Lv YG, Wang L, et al.
Predictive value of HLA-G and HLA-E in the prognosis of colorectal cancer patients.
Cell Immunol. 2015; 293(1):10-6 [PubMed] Related Publications
HLA-G and HLA-E are non-classical HLA Ib molecules. Recently, increasingly more reports have shown that HLA-G is highly expressed in different malignancies. In this article, we detected the expression levels of HLA-G and HLA-E in primary colorectal cancer patients. Our results showed that 70.6% and 65.7% of the colorectal cancer tissues had positive HLA-G or HLA-E expression, respectively, and that 46.1% positively expressed both molecules. We also analyzed the correlations between the expression levels of HLA-G, HLA-E or both combined and the clinical outcomes of the patients. Kaplan-Meier analysis results showed that the expression levels of HLA-G or HLA-E alone and the combined expression of both molecules were all statistically correlated with the overall survival of colorectal cancer patients. Cox multivariate analysis showed that only HLA-G expression can serve as independent factor for OS. Our results also showed that the expression of HLA-E was significantly correlated with tumor metastasis.

Catamo E, Zupin L, Crovella S, et al.
Non-classical MHC-I human leukocyte antigen (HLA-G) in hepatotropic viral infections and in hepatocellular carcinoma.
Hum Immunol. 2014; 75(12):1225-31 [PubMed] Related Publications
The human leukocyte antigen (HLA)-G is a "nonclassical" major histocompatibility complex (MHC) class Ib gene, located at chromosome 6, in the 6p21.3 region. The HLA-G presents immunomodulatory functions essential in pregnancy for the tolerance of the semi-allogenic fetus, but an abnormal expression of HLA-G has been observed in numerous pathological conditions, such as tumors, autoimmune diseases and viral infections. In recent years, numerous studies have assessed the clinical relevance of HLA-G expression in different types of cancer: in general, a higher HLA-G expression correlates with a lower survival rate or a shorter disease-free survival. Altered expression of HLA-G has been found in both HCV and HBV infection, and some genetic polymorphisms have been associated with altered susceptibility/disease development for these infections, however, whether the biologic role of HLA-G in HCV and HBV infection is beneficial or hazardous, it is not completely clear. In the context of hepatocellular carcinoma, HLA-G has shown a potential diagnostic role, moreover a prognostic value in HCC patients has been also attributed to HLA-G molecules. We revise here the role of HLA-G in hepatotropic HBV/HCV infections and in hepatocellular carcinoma (HCC).

Jasinski-Bergner S, Stehle F, Gonschorek E, et al.
Identification of 14-3-3β gene as a novel miR-152 target using a proteome-based approach.
J Biol Chem. 2014; 289(45):31121-35 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
Recent studies demonstrated that miR-152 overexpression down-regulates the nonclassical human leukocyte antigen (HLA) class I molecule HLA-G in human tumors thereby contributing to their immune surveillance. Using two-dimensional gel electrophoresis followed by MALDI-TOF mass spectrometry, the protein expression profile of HLA-G(+), miR-152(low) cells, and their miR-152-overexpressing (miR(high)) counterparts was compared leading to the identification of 24 differentially expressed proteins. These were categorized according to their function and localization demonstrating for most of them an important role in the initiation and progression of tumors. The novel miR-152 target 14-3-3 protein β/α/YWHAB (14-3-3β) is down-regulated upon miR-152 overexpression, although its overexpression was often found in tumors of distinct origin. The miR-152-mediated reduction of the 14-3-3β expression was accompanied by an up-regulation of BAX protein expression resulting in a pro-apoptotic phenotype. In contrast, the reconstitution of 14-3-3β expression in miR-152(high) cells increased the expression of the anti-apoptotic BCL2 gene, enhances the proliferative activity in the presence of the cytostatic drug paclitaxel, and causes resistance to apoptosis induced by this drug. By correlating clinical microarray data with the patients' outcome, a link between 14-3-3β and HLA-G expression was found, which could be associated with poor prognosis and overall survival of patients with tumors. Because miR-152 controls both the expression of 14-3-3β and HLA-G, it exerts a dual role in tumor cells by both altering the immunogenicity and the tumorigenicity.

Zhao L, Teklemariam T, Hantash BM
Heterelogous expression of mutated HLA-G decreases immunogenicity of human embryonic stem cells and their epidermal derivatives.
Stem Cell Res. 2014; 13(2):342-54 [PubMed] Related Publications
Human embryonic stem cells (hESCs) are capable of extensive self-renewal and expansion and can differentiate into any somatic tissue, making them useful for regenerative medicine applications. Allogeneic transplantation of hESC-derived tissues from results in immunological rejection absent adjunctive immunosuppression. The goal of our study was to generate a universal pluripotent stem cell source by nucleofecting a mutated human leukocyte antigen G (mHLA-G) gene into hESCs using the PiggyBac transposon. We successfully generated stable mHLA-G(EF1α)-hESC lines using chEF1α promoter system that stably expressed mHLA-G protein during prolonged undifferentiated proliferation andin differentiated embryoid bodies as well as teratomas. Morphology, karyotype, and telomerase activity of mHLA-G expressing hESC were normal. Immunofluorescence staining and flow cytometry analysis revealed persistent expression of pluripotent markers, OCT-3/4 and SSEA-4, in undifferentiated mHLA-G(EF1α)-hESC. Nucleofected hESC formed teratomas and when directed to differentiate into epidermal precursors, expressed high levels of mHLA-G and keratinocyte markers K14 and CD29. Natural killer cell cytotoxicity assays demonstrated a significant decrease in lysis of mHLA-G(EF1a)-hESC targets relative to control cells. Similar results were obtained with mHLA-G(EF1α)-hESC-derived epidermal progenitors (hEEP). One way mixed T lymphocyte reactions unveiled that mHLA-G(EF1a)-hESC and -hEEP restrained the proliferative activity of mixed T lymphocytes. We conclude that heterologous expression of mHLA-G decreases immunogenicity of hESCs and their epidermal differentiated derivatives.

Jasinski-Bergner S, Mandelboim O, Seliger B
The role of microRNAs in the control of innate immune response in cancer.
J Natl Cancer Inst. 2014; 106(10) [PubMed] Related Publications
Ligands for receptors of natural killer (NK) cells and CD8(+) cytotoxic T lymphocytes (CTL), such as the inhibitory nonclassical HLA-G, the activating stress-induced major histocompatibility complex class I-related antigens MICA and MICB, and/or the UL16-binding proteins (ULBPs), are often aberrantly expressed upon viral infection and neoplastic transformation, thereby preventing virus-infected or malignant-transformed cells from elimination by immune effector cells. Recently, it has been shown that ligands of both NK and CD8(+) T cells are regulated by a number of cellular and/or viral microRNAs (miRs). These miRs are involved in shaping the antiviral and/or antitumoral immune responses as well as neoplastic growth properties. This review summarizes the expression pattern and function of miRs directed against selected NK and T cell receptor ligands, their putative role in shaping immune surveillance and tumorigenicity, and their clinical relevance. In addition, the potential role of RNA-binding proteins in the post-transcriptional gene regulation of these ligands will be discussed.

Tao S, He H, Chen Q, Yue W
GPER mediated estradiol reduces miR-148a to promote HLA-G expression in breast cancer.
Biochem Biophys Res Commun. 2014; 451(1):74-8 [PubMed] Related Publications
Breast cancer is the most common malignant diseases in women. miR-148a plays an important role in regulation of cancer cell proliferation and cancer invasion and down-regulation of miR-148a has been reported in both estrogen receptor (ER) positive and triple-negative (TN) breast cancer. However, the regulation mechanism of miR-148a is unclear. The role of estrogen signaling, a signaling pathway is important in development and progression of breast cancer. Therefore, we speculated that E2 may regulate miR-148a through G-protein-coupled estrogen receptor-1 (GPER). To test our hypothesis, we checked the effects of E2 on miR-148a expression in ER positive breast cancer cell MCF-7 and TN cancer cell MDA-MB-231. Then we used GPER inhibitor G15 to investigate whether GPER is involved in regulation of E2 on miR-148a. Furthermore, we analyzed whether E2 affects the expression of HLA-G, which is a miR-148a target gene through GPER. The results showed that E2 induces the level of miR-148a in MCF-7 and MDA-MB-231 cells, GPER mediates the E2-induced increase in miR-148a expression in MCF-7 and MDA-MB-231 cells and E2-GPER regulates the expression of HLA-G by miR-148a. In conclusion, our findings offer important new insights into the ability of estrogenic GPER signaling to trigger HLA-G expression through inhibiting miR-148a that supports immune evasion in breast cancer.

Rutten MJ, Dijk F, Savci-Heijink CD, et al.
HLA-G expression is an independent predictor for improved survival in high grade ovarian carcinomas.
J Immunol Res. 2014; 2014:274584 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
Aberrant expression of human leukocyte antigens (HLA) class I has prognostic importance in various cancers. Here, we evaluated the prognostic value of classical (A/B/C) and nonclassical (G/E) HLA expression in 169 high grade epithelial ovarian cancer samples and linked that to clinicopathological characteristics and survival. Expression of HLA-A, -B/C, or -E was not correlated with survival. Survival was prolonged when tumours expressed HLA-G (P = 0.008) and HLA-G was an independent predictor for better survival (P = 0.011). In addition, HLA-G expression was associated with longer progression-free survival (P = 0.036) and response to chemotherapy (P = 0.014). Accordingly, high expression of HLA-G mRNA was associated with prolonged disease-free survival (P = 0.037) in 65 corresponding samples. Elevated serum-soluble HLA-G levels as measured by enzyme-linked immunosorbent assay in 50 matched patients were not correlated to HLA-G protein expression or gene expression nor with survival. During treatment, sHLA-G levels declined (P = 0.038). In conclusion, expression of HLA-G is an independent prognostic factor for improved survival in high grade epithelial ovarian cancer and a predictor for platinum sensitivity.

Zhang S, Tao Wang H
Association between HLA-G 14-bp insertion/deletion polymorphism and cancer risk: a meta-analysis.
J BUON. 2014 Apr-Jun; 19(2):567-72 [PubMed] Related Publications
PURPOSE: A number of studies have investigated the association between human leukocyte antigen-G (HLA-G) 14-bp insertion/deletion polymorphism and cancer risk, but the results remain controversial. In this study we aimed to clarify whether this association really exists.
METHODS: We carried out a meta-analysis of 8 studies including 1179 cases and 2795 controls from PubMed and Chinese language (CNKI and WanFang) databases to assess the association between the HLA-G 14-bp insertion/deletion polymorphism and cancer risk by pooled odds ratio (OR) and 95% confidence interval (CI).
RESULTS: The results showed that the HLA-G 14-bp insertion/ deletion polymorphism was not associated with total cancer risk in all genetic models (dominant model: OR=0.90, 95% CI-0.70-1.17; recessive model: OR=0.97, 95% CI=0.67-1.42; insertion/deletion (ID) vs deletion/deletion (DD):OR=0.88, 95% CI=0.66-1.18; insertion/insertion (II) vs DD: OR=0.94, 95% CI=0.62-1.41; insertion (I) vs deletion (D): OR=0.95, 95% CI=0.78-1.16). In the subgroup analysis by ethnicity, no significant association was found between Asians and Caucasians. However, subgroup analysis by cancer type showed that the polymorphism was associated with risk of hepatocellular carcinoma.
CONCLUSIONS: This meta-analysis suggests that HLA-G 14-bp insertion/deletion polymorphism may not influence the susceptibility of total cancer, but it is related to risk of hepatocellular carcinoma.

Ge YZ, Ge Q, Li MH, et al.
Association between human leukocyte antigen-G 14-bp insertion/deletion polymorphism and cancer risk: a meta-analysis and systematic review.
Hum Immunol. 2014; 75(8):827-32 [PubMed] Related Publications
BACKGROUND: Human leukocyte antigen-G (HLA-G) is involved in the development and progression of human cancers, and numerous molecular epidemiological studies have been conducted to explore the potential relationship of HLA-G 14-bp insertion/deletion (ins/del) polymorphism with cancer risk. However, results from published studies were inconclusive.
METHODS: Both PUBMED and EMBASE databases were searched comprehensively to identify eligible studies investigating the association of HLA-G 14-bp ins/del polymorphism with cancer risk. Statistical analysis was performed by using STATA 12.0 and Review Manager 5.0.
RESULTS: Fourteen eligible studies with 2340 cancer patients and 3967 controls were included and analyzed with odds ratio (OR) and its corresponding 95% confidence interval (CI). Overall, no significant association between HLA-G 14-bp ins/del polymorphism and overall cancer risk was detected in all comparison models. Further subgroup analyses based on ethnicity and cancer types demonstrated the significant association among Asians (ins/del vs. del/del: OR = 0.80, 95% CI, 0.66-0.95; ins/ins+ins/del vs. del/del: OR = 0.80, 95% CI, 0.65-0.97) and for breast cancer (ins allele vs. del allele: OR = 0.76, 95% CI, 0.61-0.96; ins/ins vs. del/del: OR = 0.57, 95% CI, 0.37-0.87; and ins/ins vs. ins/del+del/del: OR = 0.60, 95% CI, 0.42-0.87).
CONCLUSION: This study suggested that HLA-G 14-bp ins/del polymorphism might contribute to breast cancer susceptibility and overall cancer risk among Asians. Further well-designed studies with larger sample size are warranted to validate our conclusion.

Jeong S, Park S, Park BW, et al.
Human leukocyte antigen-G (HLA-G) polymorphism and expression in breast cancer patients.
PLoS One. 2014; 9(5):e98284 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
Human leukocyte antigen-G (HLA-G) is known to be implicated in a tumor-driven immune escape mechanism in malignancies. The purpose of this study was to investigate HLA-G polymorphism and expression in breast cancer. HLA-G alleles were determined by direct DNA sequencing procedures from blood samples of 80 breast cancer patients and 80 healthy controls. Soluble HLA-G (sHLA-G) was measured by enzyme-linked immunosorbent assay (ELISA) from serum specimens. HLA-G expression in breast cancer lesions was also analyzed by immunohistochemistry staining. The presence of HLA-G 3' untranslated region (UTR) 14-bp sequence was analyzed and found to be associated with reduced risk of breast cancer susceptibility based on HLA-G expression in tissues (P = 0.0407). Levels of sHLA-G were higher in the breast cancer group (median 117.2 U/mL) compared to the control group (median 10.1 U/mL, P<0.001). The area under the receiver operating characteristic curve (AU-ROC) values of sHLA-G for differentiating breast cancer from normal controls and for detecting metastasis from other stages of breast cancer were 0.89 and 0.79, respectively. HLA-G polymorphism and expression may be involved in breast carcinogenesis and sHLA-G concentrations could be used as a diagnostic marker for detecting breast cancer.

Rouas-Freiss N, Moreau P, LeMaoult J, Carosella ED
The dual role of HLA-G in cancer.
J Immunol Res. 2014; 2014:359748 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
We here review the current data on the role of HLA-G in cancer based on recent findings of an unexpected antitumor activity of HLA-G in hematological malignancies. For the past decade, HLA-G has been described as a tumor-escape mechanism favoring cancer progression, and blocking strategies have been proposed to counteract it. Aside from these numerous studies on solid tumors, recent data showed that HLA-G inhibits the proliferation of malignant B cells due to the interaction between HLA-G and its receptor ILT2, which mediates negative signaling on B cell proliferation. These results led to the conjecture that, according to the malignant cell type, HLA-G should be blocked or conversely induced to counteract tumor progression. In this context, we will here present (i) the dual role of HLA-G in solid and liquid tumors with special emphasis on (ii) the HLA-G active structures and their related ILT2 and ILT4 receptors and (iii) the current knowledge on regulatory mechanisms of HLA-G expression in tumors.

Ramos CS, Gonçalves AS, Marinho LC, et al.
Analysis of HLA-G gene polymorphism and protein expression in invasive breast ductal carcinoma.
Hum Immunol. 2014; 75(7):667-72 [PubMed] Related Publications
The human leukocyte antigen G (HLA-G) is a non-classical HLA class I molecule predominantly expressed in trophoblastic placental cells to protect the fetus during pregnancy. However, evidence has shown that this molecule may be implicated in the immune escape mechanism of tumor cells. Thus, the aim of this study was to evaluate the frequency of 14-bp insertion/deletion HLA-G polymorphism, as well as the expression of this molecule in patients with invasive breast ductal carcinoma (IDC). A significant association between the expression of HLA-G and the presence of metastasis in lymph nodes (p=0.01) was observed and the expression of HLA-G was significantly higher in patients with shorter survival time (p=0.03). The analysis suggests that the polymorphism observed in patients with IDC may be inducing a higher expression of the HLA-G molecule, which may possibly contribute to shorter survival time and a worse clinical prognosis for such patients.

Garziera M, Toffoli G
Inhibition of host immune response in colorectal cancer: human leukocyte antigen-G and beyond.
World J Gastroenterol. 2014; 20(14):3778-94 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
Colorectal cancer (CRC) is one of the most diffuse cancers worldwide and is still a clinical burden. Increasing evidences associate CRC clinical outcome to immune contexture represented by adaptive immune cells. Their type, density and location are summarized in the Immune Score that has been shown to improve prognostic prediction of CRC patients. The non-classical MHC class I human leukocyte antigen-G (HLA-G), is a crucial tumor-driven immune escape molecule involved in immune tolerance. HLA-G and soluble counterparts are able to exert inhibitory functions by direct interactions with inhibitory receptors present on both innate cells such as natural killer cells, and adaptive immune cells as cytotoxic T and B lymphocytes. HLA-G may play a prominent role in CRC strategies to avoid host immunosurveillance. This review highlights the current knowledge on HLA-G contribution in CRC, in related inflammatory diseases and in other type of cancers and disorders. HLA-G genetic setting (specific haplotypes, genotypes and alleles frequencies) and association with circulating/soluble profiles was highlighted. HLA G prognostic and predictive value in CRC was investigated in order to define a novel prognostic immune biomarker in CRC.

Locafaro G, Amodio G, Tomasoni D, et al.
HLA-G expression on blasts and tolerogenic cells in patients affected by acute myeloid leukemia.
J Immunol Res. 2014; 2014:636292 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
Human Leukocyte Antigen-G (HLA-G) contributes to cancer cell immune escape from host antitumor responses. The clinical relevance of HLA-G in several malignancies has been reported. However, the role of HLA-G expression and functions in Acute Myeloid Leukemia (AML) is still controversial. Our group identified a subset of tolerogenic dendritic cells, DC-10 that express HLA-G and secrete IL-10. DC-10 are present in the peripheral blood and are essential in promoting and maintaining tolerance via the induction of adaptive T regulatory (Treg) cells. We investigated HLA-G expression on blasts and the presence of HLA-G-expressing DC-10 and CD4(+) T cells in the peripheral blood of AML patients at diagnosis. Moreover, we explored the possible influence of the 3' untranslated region (3'UTR) of HLA-G, which has been associated with HLA-G expression, on AML susceptibility. Results showed that HLA-G-expressing DC-10 and CD4(+) T cells are highly represented in AML patients with HLA-G positive blasts. None of the HLA-G variation sites evaluated was associated with AML susceptibility. This is the first report describing HLA-G-expressing DC-10 and CD4(+) T cells in AML patients, suggesting that they may represent a strategy by which leukemic cells escape the host's immune system. Further studies on larger populations are required to verify our findings.

Smith MA, Tellier PP, Roger M, et al.
Determinants of human papillomavirus coinfections among Montreal university students: the influence of behavioral and biologic factors.
Cancer Epidemiol Biomarkers Prev. 2014; 23(5):812-22 [PubMed] Related Publications
BACKGROUND: Human papillomavirus (HPV) coinfections are common among HPV-infected individuals, but the significance and etiology of these infections remain unclear. Though current evidence suggests that women with coinfections have increased HPV exposure (i.e., more sexual partners), it is also hypothesized that these women may represent a subgroup with increased biologic susceptibility. This study sought to examine determinants of coinfections in a cohort of young women, examining both behavioral and biologic factors related to HPV acquisition over time.
METHODS: Female university students (n = 537) in Montreal, Canada, were followed for 2 years at 6-month intervals. At each visit, cervical specimens were collected for cytology and HPV testing, and women completed a questionnaire about lifestyle and behavior. HLA alleles were typed from purified DNA collected from cervical specimens. Two definitions of coinfections were used: cumulative coinfection over follow-up and concurrent coinfection at each visit. Multiple logistic regression was used to determine predictors of both cumulative and concurrent coinfections using baseline and time-dependent covariates.
RESULTS: The most consistent determinant of coinfection occurrence was number of sexual partners, though several genes of the immune response (HLA-DQB1*06:02, HLA-G*01:01:03, and HLA-G*01:01:05) were also identified as significant predictors of cumulative coinfections.
CONCLUSIONS: HPV coinfections mainly occur due to increased sexual activity, but biologic susceptibility may also be involved in a subset of women. Immunologic factors may put women at greater risk of coinfections over the long term, but short-term risk is almost exclusively driven by modifiable sexual behaviors.
IMPACT: Additional research should continue to further identify immunologic biomarkers of HPV susceptibility.

Bortolotti D, Gentili V, Rotola A, et al.
Implication of HLA-G 3' untranslated region polymorphisms in human papillomavirus infection.
Tissue Antigens. 2014; 83(2):113-8 [PubMed] Related Publications
Human papillomavirus (HPV) infection is involved in cervical lesion development. It interferes with host immune response and modifies the expression of human leukocyte antigen-G (HLA-G), a nonclassical HLA-I antigen with immune-inhibitory functions. We analyzed the frequencies of two HLA-G 3' untranslated region polymorphisms (14 bp ins/del, +3142C>G), involved in HLA-G modulation, in 33 condyloma acuminatum, 14 low grade squamous intraepithelial lesion and 100 invasive cervical cancer (ICC) HPV infected patients. We showed the involvement of HLA-G polymorphisms in HPV infection and lesion development, and suggested that 14 bp del allele promotes high-risk HPV infection, with del/C haplotype associated with ICC development. On the basis of these evidences, HLA-G polymorphisms could represent a risk factor in HPV positive subjects.

Pradhan MP, Desai A, Palakal MJ
Systems biology approach to stage-wise characterization of epigenetic genes in lung adenocarcinoma.
BMC Syst Biol. 2013; 7:141 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
BACKGROUND: Epigenetics refers to the reversible functional modifications of the genome that do not correlate to changes in the DNA sequence. The aim of this study is to understand DNA methylation patterns across different stages of lung adenocarcinoma (LUAD).
RESULTS: Our study identified 72, 93 and 170 significant DNA methylated genes in Stages I, II and III respectively. A set of common 34 significant DNA methylated genes located in the promoter section of the true CpG islands were found across stages, and these were: HOX genes, FOXG1, GRIK3, HAND2, PRKCB, etc. Of the total significant DNA methylated genes, 65 correlated with transcription function. The epigenetic analysis identified the following novel genes across all stages: PTGDR, TLX3, and POU4F2. The stage-wise analysis observed the appearance of NEUROG1 gene in Stage I and its re-appearance in Stage III. The analysis showed similar epigenetic pattern across Stage I and Stage III. Pathway analysis revealed important signaling and metabolic pathways of LUAD to correlate with epigenetics. Epigenetic subnetwork analysis identified a set of seven conserved genes across all stages: UBC, KRAS, PIK3CA, PIK3R3, RAF1, BRAF, and RAP1A. A detailed literature analysis elucidated epigenetic genes like FOXG1, HLA-G, and NKX6-2 to be known as prognostic targets.
CONCLUSION: Integrating epigenetic information for genes with expression data can be useful for comprehending in-depth disease mechanism and for the ultimate goal of better target identification.

Rizzo R, Audrito V, Vacca P, et al.
HLA-G is a component of the chronic lymphocytic leukemia escape repertoire to generate immune suppression: impact of the HLA-G 14 base pair (rs66554220) polymorphism.
Haematologica. 2014; 99(5):888-96 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
This work investigates the possibility that HLA-G, a molecule modulating innate and adaptive immunity, is part of an immune escape strategy of chronic lymphocytic leukemia cells. A 14 base pair insertion/deletion polymorphism (rs66554220) in the 3'-untranslated region of HLA-G influences mRNA stability and protein expression. The analysis of a cohort of patients with chronic lymphocytic leukemia confirmed that del/del individuals are characterized by higher levels of surface and soluble HLA-G than subjects with the other two genotypes. In line with its role in immunomodulation, the percentage of regulatory T lymphocytes is higher in del/del patients than in patients with the other genotypes and correlates with the amounts of surface or soluble HLA-G. Furthermore, addition of sHLA-G-rich plasma from patients with chronic lymphocytic leukemia induces natural killer cell apoptosis and impairs natural killer cell lysis, with effects proportional to the amount of soluble HLA-G added. Lastly, the presence of an HLA-G 14 base pair polymorphism is of prognostic value, with del/del patients showing reduced overall survival, as compared to those with other genotypes. These results suggest that: (i) the HLA-G 14 base pair polymorphism influences the levels of surface and soluble HLA-G expression, and (ii) the over-expression of HLA-G molecules contributes to creating tolerogenic conditions.

Smallridge RC, Chindris AM, Asmann YW, et al.
RNA sequencing identifies multiple fusion transcripts, differentially expressed genes, and reduced expression of immune function genes in BRAF (V600E) mutant vs BRAF wild-type papillary thyroid carcinoma.
J Clin Endocrinol Metab. 2014; 99(2):E338-47 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
CONTEXT: The BRAF V600E mutation (BRAF-MUT) confers an aggressive phenotype in papillary thyroid carcinoma, but unidentified additional genomic abnormalities may be required for full phenotypic expression.
OBJECTIVE: RNA sequencing (RNA-Seq) was performed to identify genes differentially expressed between BRAF-MUT and BRAF wild-type (BRAF-WT) tumors and to correlate changes to patient clinical status.
DESIGN: BRAF-MUT and BRAF-WT tumors were identified in patients with T1N0 and T2-3N1 tumors evaluated in a referral medical center. Gene expression levels were determined (RNA-Seq) and fusion transcripts were detected. Multiplexed capture/detection and digital counting of mRNA transcripts (nCounter, NanoString Technologies) validated RNA-Seq data for immune system-related genes.
PATIENTS: BRAF-MUT patients included nine women, three men; nine were TNM stage I and three were stage III. Three (25%) had tumor infiltrating lymphocytes. BRAF-WT included five women, three men; all were stage I, and five (62.5%) had tumor infiltrating lymphocytes.
RESULTS: RNA-Seq identified 560 of 13 085 genes differentially expressed between BRAF-MUT and BRAF-WT tumors. Approximately 10% of these genes were related to MetaCore immune function pathways; 51 were underexpressed in BRAF-MUT tumors, whereas 4 (HLAG, CXCL14, TIMP1, IL1RAP) were overexpressed. The four most differentially overexpressed immune genes in BRAF-WT tumors (IL1B; CCL19; CCL21; CXCR4) correlated with lymphocyte infiltration. nCounter confirmed the RNA-Seq expression level data. Eleven different high-confidence fusion transcripts were detected (four interchromosomal; seven intrachromosomal) in 13 of 20 tumors. All in-frame fusions were validated by RT-PCR.
CONCLUSION: BRAF-MUT papillary thyroid cancers have reduced expression of immune/inflammatory response genes compared with BRAF-WT tumors and correlate with lymphocyte infiltration. In contrast, HLA-G and CXCL14 are overexpressed in BRAF-MUT tumors. Sixty-five percent of tumors had between one and three fusion transcripts. Functional studies will be required to determine the potential role of these newly identified genomic abnormalities in contributing to the aggressiveness of BRAF-MUT and BRAF-WT tumors.

Yang YC, Chang TY, Chen TC, et al.
Human leucocyte antigen-G polymorphisms are associated with cervical squamous cell carcinoma risk in Taiwanese women.
Eur J Cancer. 2014; 50(2):469-74 [PubMed] Related Publications
BACKGROUND: The mere presence of human papillomavirus (HPV) is not enough for cervical cancer development and immunogenetic background may play an important role. Human leucocyte antigen (HLA)-G acts as a negative regulator of immune responses and its expression in tumour cells may enable them to avoid immune attack. We aim to study if polymorphisms in the HLA-G gene are associated with cervical cancer risk in Taiwanese women.
METHODS: +1537 A/C, 14-bp deletion/insertion (Del/Ins), and +3142 G/C polymorphisms were genotyped in a hospital-based study of 317 women with cervical squamous cell carcinoma (CSCC) and 400 healthy control women frequency matched by age. The presence and genotypes of HPV in CSCC were determined.
RESULTS: We found the +3142 C/C genotype and C allele were associated with increased risk for CSCC (adjusted odds ratio [OR]=1.78, P=0.004; adjusted OR=1.31, P=0.014, respectively). In subgroup analysis based on HPV type 16 positivity, significant associations with higher adjusted ORs were found in +3142 C/C genotype and C allele (adjusted OR=2.19, P=0.001; adjusted OR=1.48, P=0.003, respectively) and +1537 C/C genotype and C allele frequencies increased significantly (adjusted OR=2.88, P=0.004; adjusted OR=1.69, P=0.0005, respectively). Furthermore, the C-Del-C haplotype conferred increased risk of both CSCC and HPV-16 positive CSCC women (adjusted OR=1.41, P=0.009; adjusted OR=1.94, P=0.0001, respectively).
CONCLUSION: These findings suggest that HLA-G gene is involved in the susceptibility to CSCC.

Eskandari-Nasab E, Hashemi M, Hasani SS, et al.
Association between HLA-G 3'UTR 14-bp ins/del polymorphism and susceptibility to breast cancer.
Cancer Biomark. 2013; 13(4):253-9 [PubMed] Related Publications
Human leukocyte antigen G (HLA-G) is a non-classic major histocompatibility complex (MHC) class I molecule that is highly expressed in cancer pathologies. A 14-bp insertion/deletion polymorphism in exon 8 of the 3' untranslated region (3'-UTR) of the HLA-G gene has been suggested to be associated with HLA-G mRNA stability and the expression of HLA-G. This study aimed to evaluate the association of 14-bp ins/del polymorphism in HLA-G gene and breast cancer in a south-east Iranian population. This study was performed using 236 patients with breast cancer and 203 healthy subjects. We designed a rapid and simple bi-directional PCR allele-specific amplification (Bi-PASA) for detection of 14-bp ins/del polymorphism in the HLA-G gene. The results of our study revealed that the prevalence of HLA-G 14-bp homozygote deletion genotype was higher in breast cancer patients than in the control group (OR=2.06, 95%CI=1.23-3.44, P=0.006). The frequency of the Del allele was 56.4% in breast cancer patients and 46.5% in the control group and the difference was statistically significant (OR=1.48, 95%CI=1.13-1.94, P=0.004). Moreover we evaluated the possible correlation of the HLA-G 14-bp ins/del genotypes and clinical characteristics of the patients, but no statistically significant correlation was found (P> 0.05). Our findings, for the first time, suggest that the 14-bp insertion/deletion polymorphism in HLA-G gene could be a genetic risk factor for the susceptibility to breast carcinoma. Further studies on larger populations with different ethnicities are required to verify our findings.

Zeestraten EC, Reimers MS, Saadatmand S, et al.
Combined analysis of HLA class I, HLA-E and HLA-G predicts prognosis in colon cancer patients.
Br J Cancer. 2014; 110(2):459-68 [PubMed] Article available free on PMC after 07/11/2015 Related Publications
BACKGROUND: Evasion of immune surveillance and suppression of the immune system are important hallmarks of tumour development in colon cancer. The goal of this study was to establish a tumour profile based on biomarkers that reflect a tumour's immune susceptibility status and to determine their relation to patient outcome.
METHODS: The study population consisted of 285 stage I-IV colon cancer patients of which a tissue micro array (TMA) was available. Sections were immunohistochemically stained for the presence of Foxp3+ cells and tumour expression of HLA Class I (HLA-A, -B, -C) and non-classical HLA-E and HLA-G. All markers were combined for further analyses, resulting in three tumour immune phenotypes: strong immune system tumour recognition, intermediate immune system tumour recognition and poor immune system tumour recognition.
RESULTS: Loss of HLA class I expression was significantly related to a better OS (P-value 0.005) and DFS (P-value 0.008). Patients with tumours who showed neither HLA class I nor HLA-E or -G expression (phenotype a) had a significant better OS and DFS (P-value <0.001 and 0.001, respectively) compared with phenotype b (OS HR: 4.7, 95% CI: 1.2-19.0, P=0.001) or c (OS HR: 8.2, 95% CI: 2.0-34.2, P=0.0001). Further, the tumour immune phenotype was an independent predictor for OS and DFS (P-value 0.009 and 0.013, respectively).
CONCLUSION: Tumours showing absence of HLA class I, HLA-E and HLA-G expressions were related to a better OS and DFS. By combining the expression status of several immune-related biomarkers, three tumour immune phenotypes were created that related to patient outcome. These immune phenotypes represented significant, independent, clinical prognostic profiles in colon cancer.

Rolfsen GB, Castelli EC, Donadi EA, et al.
HLA-G polymorphism and breast cancer.
Int J Immunogenet. 2014; 41(2):143-8 [PubMed] Related Publications
The aim of this study was to explore a possible influence of the HLA-G coding polymorphisms on the susceptibility to breast cancer development in Brazilian subjects; however, none of the HLA-G variation sites evaluated was influencing breast cancer susceptibility indicating that the variation in the HLA-G coding region is not a risk factor for breast cancer.

Trivanović D, Nikolić S, Krstić J, et al.
Characteristics of human adipose mesenchymal stem cells isolated from healthy and cancer affected people and their interactions with human breast cancer cell line MCF-7 in vitro.
Cell Biol Int. 2014; 38(2):254-65 [PubMed] Related Publications
Adipose tissue is an attractive source of mesenchymal stem/stromal cells (MSCs) with potential applications in reconstructive plastic surgery and regenerative medicine. The aim of this study was to characterise human adipose tissue MSCs (ASCs) derived from healthy individuals and cancer patients and to compare their interactions with tumour cells. ASCs were isolated from adipose tissue of healthy donors, breast cancer-adjacent adipose tissue of breast cancer patients and tumour-adjacent adipose tissue of non-breast cancer patients. Their proliferation, differentiation, immunophenotype and gene expression were assessed and effects on the proliferation of human breast cancer cell line MCF-7 compared. ASCs from all sources exhibited similar morphology, proliferative and differentiation potential, showing the characteristic pattern of mesenchymal surface markers expression (CD90, CD105, CD44H, CD73) and the lack of HLA-DR and hematopoietic markers (CD11a, CD33, CD45, Glycophorin-CD235a), but uneven expression of CD34. ASCs also shared a common positive gene expression of HLA-DR, HLA-A, IL-6, TGF-β and HIF-1, but were negative for HLA-G, while the expression levels of Cox-2 and IDO-1 varied. All ASCs significantly stimulated the proliferation of MCF-7 tumour cells in direct mixed co-cultures and transwell system, although their conditioned media displayed antiproliferative activity. Data obtained showed that ASCs with similar characteristics are easily isolated from various donors and sites of origin, although ASCs could both suppress and favour tumour cells growth, emphasising the importance of cellular context within the microenvironment and pointing to the significance of safety studies to exclude any potential clinical risk of their application in regenerative medicine.

Tremante E, Ginebri A, Lo Monaco E, et al.
A melanoma immune response signature including Human Leukocyte Antigen-E.
Pigment Cell Melanoma Res. 2014; 27(1):103-12 [PubMed] Related Publications
Paired cultures of early-passage melanoma cells and melanocytes were established from metastatic lesions and the uninvolved skin of five patients. In this stringent autologous setting, cDNA profiling was used to analyze a subset of 1477 genes selected by the Gene Ontology term 'immune response'. Human Leukocyte Antigen E (HLA-E) was ranked 19th among melanoma-overexpressed genes and was embedded in a transformation signature including its preferred peptide ligand donors HLA-A, HLA-B, HLA-C, and HLA-G. Mostly undetectable in normal skin and 39 nevi (including rare and atypical lesions), HLA-E was detected by immunohistochemistry in 17/30 (57%) and 32/48 (67%) primary and metastatic lesions, respectively. Accordingly, surface HLA-E was higher on melanoma cells than on melanocytes and protected the former (6/6 cell lines) from lysis by natural killer (NK) cells, functionally counteracting co-expressed triggering ligands. Although lacking HLA-E, melanocytes (4/4 cultures) were nevertheless (and surprisingly) fully protected from NK cell lysis.

Dadkhah E, Naseh H, Farshchian M, et al.
A cancer-array approach elucidates the immune escape mechanism and defects in the DNA repair system in esophageal squamous cell carcinoma.
Arch Iran Med. 2013; 16(8):463-70 [PubMed] Related Publications
BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is the second-most frequently diagnosed cancer in Northeast Iran, often diagnosed in advanced stages. No standard early diagnostic guideline has been proposed to date and current therapeutic modalities are not effective. Detection of tumor-specific biomarkers, which is the goal of this study, could prove useful in the diagnosis of ESCC. 
METHODS: To better understand the gene expression profile of ESCC, we analyzed tumor samples and corresponding adjacent normal tissues from ESCC patients by Chemiluminescent Human Cancer GEArrays. Candidate genes were verified by real-time PCR. 
RESULTS: Out of 440 cancer-related genes included in the array, 71 were overexpressed compared to normal tissue, with significant differences in 11 genes. There were 108 genes underexpressed, with significant differences in 5 genes. Until now, the AP2M1, FTL, UBE2L6, HLA-C, and HSPA8 overexpressed genes and XRCC5, TP53I3 and RAP1A underexpressed genes were not reported in ESCC. We chose the MMP2, HLA-G, and XRCC5 markers from 58 Iranian ESCC patients to verify the expression validity by real-time PCR. The microarray results were confirmed with two-tailed significance levels of P = 0.003 (MMP2), P = 0.000 (HLA-G) and P = 0.002(XRCC5). Analysis performed for the candidate genes using GNCpro online software highlighted two pathways, an immuno-modulatory response and DNA replication and repair. We successfully performed and validated Chemiluminescent GEArray gene expression profiling in ESCC. Several biomarkers that might be related to tumorigenesis in ESCC were identified.
CONCLUSION: Immuno-modulatory and DNA repair pathways could be used as targets to locate specific diagnostic, prognostic, and therapeutic biomarkers for ESCC.

Hu J, Li L, Liu Y, et al.
Overexpression of HLA-G Is positively associated with Kazakh esophageal squamous cell carcinoma in Xinjiang, China.
Viral Immunol. 2013; 26(3):180-4 [PubMed] Related Publications
HLA-G is a class I HLA that has gained much attention due to its multiple functions in the immune system. More important, some studies found HLA-G may be detrimental in tumors and viral infections, and the detection of HLA-G expression might serve as a clinical marker in the prediction of clinical outcomes for certain types of carcinoma. We assessed the association between the development of Kazakh esophageal squamous cell carcinoma (ESCC) harboring high-risk HPV infection and the expression of HLA-G. The expression of HLA-G was detected by S-P immunohistochemical staining in 60 cases of Kazakh ESCC tissues and 40 cases of Kazakh tumor adjacent normal tissues. HPV16 infection in ESCC was detected by genotype-specific polymerase chain reaction. HPV16 infection rate in Kazakh ESCC was 35.0%, significantly higher than that of the infection rate of the adjacent normal tissues 15% (p<0.05, OR=3.051; 95% CI: 1.103-8.438). The expression of HLA-G in Kazakh ESCC was 75.0% (45/60), significantly higher than that of tumor adjacent normal tissues (17.5%; p<0.05); expression of HLA-G was slightly higher in HPV16-positive than HPV16-negative ESCC, but the difference was not statistically significant (p>0.05). The positive expression rate of HLA-G was closely related to depth of invasion and clinical stage (p<0.05 for all), but was not related to age, sex, tumor location, histologic grade, and nodal status (p>0.05 for all). Overexpression of HLA-G was a characteristic feature of Kazakh ESCC; HLA-G may be involved in Kazakh ESCC carcinogenesis and HPV infection.

Cutucache CE
Tumor-induced host immunosuppression: special focus on CLL.
Int Immunopharmacol. 2013; 17(1):35-41 [PubMed] Related Publications
Malignant cells are able to suppress host immune responses in an effort to avoid immune detection in vivo. Tumor-induced immunosuppression can be achieved at the molecular, cellular, and/or physiological levels. Herein the contribution of immune-tolerant genes and regulatory cells to immunosuppression related to alterations of T-cells and antigen-presentation is reviewed. Furthermore, key advances in countering tumor-induced immunosuppression are described in reference to immune evasion mechanisms used by chronic lymphocytic leukemia (CLL) cells. Lastly, the challenges associated with targeting the tumor microenvironment coupled with the usefulness of immunomodulatory drugs are discussed. This review summarizes select immune evasion tactics orchestrated by the conversation between CLL cells and their microenvironment.

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