Association between FAS polymorphism and prostate cancer development

Fas and microRNAs Variations as a Possible Risk for Behçet Disease

BACKGROUND

Behçet disease (BD) belongs to a disease family that has a transparent borderline between autoinflammatory and autoimmune disorders. Fas and some miRNAs have revealed to display remarkable roles in both autoimmune and autoinflammatory processes, and they can play important roles in defective apoptosis in BD. We investigated the association of the susceptibility of BD with Fas, miRNA variations, and their both single and combined presence in a Turkish population as a case-control study.

METHODS

The distributions of FAS-670 A>G rs1800682, mir146a rs2910164, and mir196a rs11614913 polymorphisms are analyzed with the polymerase chain reaction-restriction fragment length polymorphism method in 115 BD patients and 220 controls in 6-month period.

RESULTS

Statistical analysis indicates that in the case of Fas-670 A/G rs1800682, AA genotype and A allele have a protective role in BD (p = 0.0004 and p = 0.0009, respectively). The dominant model (AA + AG/GG) also displays a protective effect on BD unlike the recessive model (p = 0.03). In addition, both homozygous genotype (CC) of rs2910164 of mir-146a (p = 0.04) and the dominant model (CC + CG vs. GG) have protective effects on BD unlike the recessive model (p < 0.0001). Both mir-196a2 rs1800682 polymorphism and combined genotype analysis of rs1800682-rs2910164 and rs1800682-rs11614913 gave no statistically significant differences within the groups for genotypes and either of the alleles (p > 0.05).

CONCLUSIONS

These findings indicate that both Fas rs1800682 and mir-146a rs2910164 variants might be important factors participating in the protection against BD in the Turkish population.

Intrinsic and extrinsic pathways of apoptosis: Role in cancer development and prognosis

Apoptosis, also named programmed cell death, is a fundament process required for morphogenetic homeostasis during early development and in pathophysiological conditions. It is come into existence in 1972 by work of Kerr, Wyllie and Currie and later on investigated during the research on development of the C. elegans. Trigger by several stimuli, apoptosis is necessary during the embryonic development and aging as homeostatic mechanism to control the cell population and also play a key role as defense mechanism against the immune responses and elimination of damaged cells. Cancer, a genetic disease, is a growing burden on the health and economy of both developing and developed countries. Every year there is tremendously increasing in the number of new cancer cases and mortality rate. Although, there is a significant improvement have been made in biotechnological and bioinformatic fields however, the therapeutic advantages and cancer etiology is still under explored. Several studies determined the deregulation of different apoptotic components during the cancer development and progression. Apoptosis relies on activation of distinct signaling pathways that are often deregulated in cancer. Thus, exploring the single or more than one apoptotic component underlying their expression in carcinogenesis could help to track the disease progression. Current book chapter will provide the several evidences supporting the use of different apoptotic components as prognosis and prediction markers in various human cancer types.

PVT1 signals an androgen-dependent transcriptional repression program in prostate cancer cells and a set of the repressed genes predicts high-risk tumors

BACKGROUND

Androgen receptor (AR) and polycomb repressive complex 2 (PRC2) are known to co-occupy the loci of genes that are downregulated by androgen-stimulus. Long intergenic non-coding RNA (lincRNA) PVT1 is an overexpressed oncogene that is associated with AR in LNCaP prostate cancer cells, and with PRC2 in HeLa and many other types of cancer cells. The possible involvement of PVT1 in mediating androgen-induced gene expression downregulation in prostate cancer has not been explored.

METHODS

LNCaP cell line was used. Native RNA-binding-protein immunoprecipitation with anti-AR or anti-EZH2 was followed by RT-qPCR with primers for PVT1. Knockdown of PVT1 with specific GapmeRs (or a control with scrambled GapmeR) was followed by differentially expressed genes (DEGs) determination with Agilent microarrays and with Significance Analysis of Microarrays statistical test. DEGs were tested as a tumor risk classifier with a machine learning Random Forest algorithm run with gene expression data from all TCGA-PRAD (prostate adenocarcinoma) tumors as input. ChIP-qPCR was performed for histone marks at the promoter of one DEG.

RESULTS

We show that PVT1 knockdown in androgen-stimulated LNCaP cells caused statistically significant expression upregulation/downregulation of hundreds of genes. Interestingly, PVT1 knockdown caused upregulation of 160 genes that were repressed by androgen, including a significantly enriched set of tumor suppressor genes, and among them FAS, NOV/CCN3, BMF, HRK, IFIT2, AJUBA, DRAIC and TNFRSF21. A 121-gene-set (out of the 160) was able to correctly predict the classification of all 293 intermediate- and high-risk TCGA-PRAD tumors, with a mean ROC area under the curve AUC = 0.89 ± 0.04, pointing to the relevance of these genes in cancer aggressiveness. Native RIP-qPCR in LNCaP showed that PVT1 was associated with EZH2, a component of PRC2. PVT1 knockdown followed by ChIP-qPCR showed significant epigenetic remodeling at the enhancer and promoter regions of tumor suppressor gene NOV, one of the androgen-repressed genes that were upregulated upon PVT1 silencing.

CONCLUSIONS

Overall, we provide first evidence that PVT1 was involved in signaling a genome-wide androgen-dependent transcriptional repressive program of tumor suppressor protein-coding genes in prostate cancer cells. Identification of transcriptional inhibition of tumor suppressor genes by PVT1 highlights the pathway to the investigation of mechanisms that lie behind the oncogenic role of PVT1 in cancer. Video Abstract.

Association analysis of FAS-670A/G and FASL-844C/T polymorphisms with risk of generalized aggressive periodontitis disease

The interaction of FAS/FAS ligand (FASL) serves an important role in the upregulation of apoptotic processes through different mechanisms in cells. Previous studies have established that the polymorphisms FAS-670A/G and FASL-844C/T are associated with risk of generalized aggressive periodontitis (GAP) in different ethnic populations. Therefore, in the present study, it was investigated for the first time whether FAS-670A/G and FASL-844C/T polymorphisms were associated with risk of GAP in Iran. This case-control study performed the polymerase chain reaction-restriction fragment length polymorphism method in 25 patients with GAP and 110 normal subjects as controls. The results indicated that there was no significant difference in FAS-670A/G genotype frequency between the GAP and control groups. A higher frequency of the combined genotype (AG+GG) was observed in the GAP patients (96.0%) compared with the control subjects (90.9%), though this was not significant [χ²=0.705, degrees of freedom (df)=1, P=0.401]. Similarly, the prevalence of the G allele was non-significantly higher in the GAP group (62.0%) compared with that in the controls (60.0%; χ²=0.012, df=1, P=0.913). For FASL-844C/T polymorphism, the frequency of the combined genotype (CT+TT) was higher in the GAP group (96.0%) when compared with the control subjects (91.8%); however its association was not statistically significant (χ²=0.519, df=1, P=0.471). The frequency of the T allele only marginally differed between the groups, being 60.0% in the GAP group and 50.9% in the controls (χ²=3.627, df=1, P=0.057). These results indicated that there were no significant associations between the FAS-670A/G and FASL-844C/T polymorphisms and the risk of disease in GAP patients when compared with normal individuals.

Association of FAS-670A/G and FASL-844C/T polymorphisms with idiopathic azoospermia in Western Iran

OBJECTIVE

The FAS/FASL interaction plays a central role in up-regulation of apoptosis in testis. Studies indicated that the FAS-670A/G and FASL-844C/T polymorphisms are associated with the risk of idiopathic azoospermia in different ethnic groups. Therefore, the current study aims to investigate the association between FAS-670A/G and FASL-844C/T polymorphisms with male idiopathic infertility in Western Iran.

STUDY DESIGN

The analysis of FAS-670A/G and FASL-844C/T polymorphisms were carried out using the PCR-RFLP approach, on 102 infertile men and 110 normal fertile men as control group.

RESULTS

The results suggested that there were no significant difference in genotypic frequencies of FAS-670A/G polymorphism between infertile and control groups. On the other hand, significant result was observed for the frequency of FASL-844C/T polymorphism in infertile men in comparison to control group (P=0.02). Indeed, men with FASL-844TT and CT genotypes had an increased risk of idiopathic azoospermia in comparison to those with CC genotype (OR=2.02, 95% CI [1.05-3.88, P=0.03] and OR=1.44, 95% CI [0.46-4.49, P=0.53]), respectively.

CONCLUSION

Our findings speculate that the FASL-844C/T polymorphism is associated with the risk of male infertility and this variation can be considered as a genetic risk factor for idiopathic azoospermia among Western Iranian men population. Summing up, these data indicated that the genetic variations in FAS/FASL system have a critical role in spermatogenesis defects and subsequent male infertility.

Identification of novel prostate cancer drivers using RegNetDriver: a framework for integration of genetic and epigenetic alterations with tissue-specific regulatory network

We report a novel computational method, RegNetDriver, to identify tumorigenic drivers using the combined effects of coding and non-coding single nucleotide variants, structural variants, and DNA methylation changes in the DNase I hypersensitivity based regulatory network. Integration of multi-omics data from 521 prostate tumor samples indicated a stronger regulatory impact of structural variants, as they affect more transcription factor hubs in the tissue-specific network. Moreover, crosstalk between transcription factor hub expression modulated by structural variants and methylation levels likely leads to the differential expression of target genes. We report known prostate tumor regulatory drivers and nominate novel transcription factors (ERF, CREB3L1, and POU2F2), which are supported by functional validation.

Sildenafil (Viagra) sensitizes prostate cancer cells to doxorubicin-mediated apoptosis through CD95

We previously reported that Sildenafil enhances apoptosis and antitumor efficacy of doxorubicin (DOX) while attenuating its cardiotoxic effect in prostate cancer. In the present study, we investigated the mechanism by which sildenafil sensitizes DOX in killing of prostate cancer (PCa) cells, DU145. The death receptor Fas (APO-1 or CD95) induces apoptosis in many carcinoma cells, which is negatively regulated by anti-apoptotic molecules such as FLIP (Fas-associated death domain (FADD) interleukin-1-converting enzyme (FLICE)-like inhibitory protein). Co-treatment of PCa cells with sildenafil and DOX for 48 hours showed reduced expression of both long and short forms of FLIP (FLIP-L and -S) as compared to individual drug treatment. Over-expression of FLIP-s with an adenoviral vector attentuated the enhanced cell-killing effect of DOX and sildenafil. Colony formation assays also confirmed that FLIP-S over-expression inhibited the DOX and sildenafil-induced synergistic killing effect as compared to the cells infected with an empty vector. Moreover, siRNA knock-down of CD95 abolished the effect of sildenafil in enhancing DOX lethality in cells, but had no effect on cell killing after treatment with a single agent. Sildenafil co-treatment with DOX inhibited DOX-induced NF-κB activity by reducing phosphorylation of IκB and nuclear translocation of the p65 subunit, in addition to down regulation of FAP-1 (Fas associated phosphatase-1, a known inhibitor of CD95-mediated apoptosis) expression. This data provides evidence that the CD95 is a key regulator of sildenafil and DOX mediated enhanced cell death in prostate cancer.

FAS -670 A/G polymorphism may be associated with the depletion of CD4(+) T lymphocytes in HIV-1 infection

In this study, the polymorphisms in the FAS and FASL genes was investigated in a sample of 198 HIV-1-seropositive individuals and 191 seronegative controls to evaluate a possible association between polymorphisms and the infection. The identification of the A and G alleles of the FAS -670 polymorphism was accomplished through polymerase chain reaction assays followed by digestion with the restriction enzyme MvaI. The identification of the A and G alleles of the FAS -124 polymorphism and the T and delT alleles of the FAS -169 polymorphism were performed using the amplification-created restriction site method followed by restriction fragment length polymorphism reactions. The comparative analysis of allelic and genotypic frequencies between the groups did not reveal any significant differences. However, the quantitative analysis of CD4(+) T lymphocytes suggests that the G allele of the FAS -670 A/G polymorphism can be a protective factor against the depletion of these cells in the course of an HIV-1 infection. Polymorphisms in the FAS and FASL genes were not associated with the number of CD8(+) T lymphocytes or the plasma viral load. Our findings suggest that the FAS -670 polymorphism may be associated with apoptosis of CD4(+) T lymphocytes after infection by HIV-1.

Exploring prostate cancer genome reveals simultaneous losses of PTEN, FAS and PAPSS2 in patients with PSA recurrence after radical prostatectomy

The multifocal nature of prostate cancer (PCa) creates a challenge to patients' outcome prediction and their clinical management. An approach that scrutinizes every cancer focus is needed in order to generate a comprehensive evaluation of the disease, and by correlating to patients' clinico-pathological information, specific prognostic biomarker can be identified. Our study utilized the Affymetrix SNP 6.0 Genome-wide assay to investigate forty-three fresh frozen PCa tissue foci from twenty-three patients. With a long clinical follow-up period that ranged from 2.0-9.7 (mean 5.4) years, copy number variation (CNV) data was evaluated for association with patients' PSA status during follow-up. From our results, the loss of unique genes on 10q23.31 and 10q23.2-10q23.31 were identified to be significantly associated to PSA recurrence (p < 0.05). The implication of PTEN and FAS loss (10q23.31) support previous reports due to their critical roles in prostate carcinogenesis. Furthermore, we hypothesize that the PAPSS2 gene (10q23.2-10q23.31) may be functionally relevant in post-operative PSA recurrence because of its reported role in androgen biosynthesis. It is suggestive that the loss of the susceptible region on chromosome 10q, which implicates PTEN, FAS and PAPSS2 may serve as genetic predictors of PSA recurrence after radical prostatectomy.

Soluble fas and the -670 polymorphism of fas in lupus nephritis

This study was performed to clarify the role of soluble Fas (sFas) in lupus nephritis (LN) and establish a potential relationship between LN and the −670 polymorphism of Fas in 67 patients with systemic lupus erythematosus (SLE), including a subset of 24 LN patients with proteinuria. Additionally, a group of 54 healthy subjects (HS) was included. The allelic frequency of the −670 polymorphism of Fas was determined using PCR-RFLP analysis, and sFas levels were assessed by ELISA. Additionally, the WT-1 protein level in urine was measured. The Fas receptor was determined in biopsies by immunohistochemistry (IHC) and in situ hybridization (FISH) and apoptotic features by TUNEL. Results. The −670 Fas polymorphism showed that the G allele was associated with increased SLE susceptibility, with an odds ratio (OR) of 1.86. The sFas was significantly higher in LN patients with the G/G genotype, and this subgroup exhibited correlations between the sFas level and proteinuria and increased urinary WT-1 levels. LN group shows increased expression of Fas and apoptotic features. In conclusion, our results indicate that the G allele of the −670 polymorphism of Fas is associated with genetic susceptibility in SLE patients with elevated levels of sFas in LN with proteinuria.

Association of the polymorphisms in the Fas/FasL promoter regions with cancer susceptibility: a systematic review and meta-analysis of 52 studies

Fas and its ligand (FasL) play an important role in apoptosis and carcinogenesis. Therefore, the potential association of polymorphisms in the Fas (-670A>G, rs1800682; -1377G>A, rs2234767) and FasL (-844C>T, rs763110) with cancer risk has been widely investigated. However, all the currently available results are not always consistent. In this work, we performed a meta-analysis to further determine whether carriers of the polymorphisms in Fas and FasL of interest could confer an altered susceptibility to cancer. All relevant data were retrieved by PubMed and Web of Science, and 52 eligible studies were chosen for this meta-analysis. There was no association of the Fas -670A>G polymorphism with cancer risk in the pooled data. For the Fas -1377G>A and FasL -844C>T polymorphisms, results revealed that the homozygotes of -1377A and -844C were associated with elevated risk of cancer as a whole. Further stratified analysis indicated markedly increased risk for developing breast cancer, gastric cancer, and esophageal cancer, in particular in Asian population. We conclude that carriers of the Fas-1377A and the FasL -844C are more susceptible to the majority of cancers than non-carriers.

Dissecting the expression landscape of RNA-binding proteins in human cancers

BACKGROUND

RNA-binding proteins (RBPs) play important roles in cellular homeostasis by controlling gene expression at the post-transcriptional level.

RESULTS

We explore the expression of more than 800 RBPs in sixteen healthy human tissues and their patterns of dysregulation in cancer genomes from The Cancer Genome Atlas project. We show that genes encoding RBPs are consistently and significantly highly expressed compared with other classes of genes, including those encoding regulatory components such as transcription factors, miRNAs and long non-coding RNAs. We also demonstrate that a set of RBPs, numbering approximately 30, are strongly upregulated (SUR) across at least two-thirds of the nine cancers profiled in this study. Analysis of the protein-protein interaction network properties for the SUR and non-SUR groups of RBPs suggests that path length distributions between SUR RBPs is significantly lower than those observed for non-SUR RBPs. We further find that the mean path lengths between SUR RBPs increases in proportion to their contribution to prognostic impact. We also note that RBPs exhibiting higher variability in the extent of dysregulation across breast cancer patients have a higher number of protein-protein interactions. We propose that fluctuating RBP levels might result in an increase in non-specific protein interactions, potentially leading to changes in the functional consequences of RBP binding. Finally, we show that the expression variation of a gene within a patient group is inversely correlated with prognostic impact.

CONCLUSIONS

Overall, our results provide a roadmap for understanding the impact of RBPs on cancer pathogenesis.

FAS and FASL gene polymorphisms are not associated with hepatitis B virus infection based on a case-control study in a Brazilian population

Objective. This study investigated the association of the single nucleotide polymorphisms (SNPs) in the FAS and FASL genes with the outcome of hepatitis B virus (HBV) infection. Methods. Blood samples were collected from 116 HBV-infected patients at the Hospital of the Santa Casa de Misericordia Foundation (Belém, PA, Brazil). Seronegative individuals were used as controls. DNA samples were extracted from the leukocytes and assayed using the polymerase chain reaction (PCR) followed by RFLP analysis with restriction endonucleases. Results. The frequencies of the mutant genotypes for -670FAS (GG), Ivs2nt-124FASL (GG), Ivs3nt-169FASL (ΔT/ΔT), and -844FASL (TT) were higher in the HBV patients, and the FAS-1377AA genotype was more frequent in the control group; however, the differences between the allele and genotype frequencies were not statistically significant. When the HBV patient population was divided into two groups (inactive carriers and active chronic hepatitis patients), the mutant genotypes were found to be more prevalent in the active chronic hepatitis group with respect to the FAS gene polymorphisms; however, this difference was not statistically significant. Conclusions. The results suggest that the polymorphisms in FAS and FASL genes are not associated with HBV infection or even with the natural history of the infection in the Brazilian Amazon region.

FASL polymorphism is associated with response to bacillus Calmette-Guérin immunotherapy in bladder cancer

OBJECTIVE

Deregulation of FAS/FASL system may lead to immune escape and influence bacillus Calmette-Guérin (BCG) immunotherapy outcome, which is currently the gold standard adjuvant treatment for high-risk non-muscle invasive bladder tumors. Among other events, functional promoter polymorphisms of FAS and FASL genes may alter their transcriptional activity. Therefore, we aim to evaluate the role of FAS and FASL polymorphisms in the context of BCG therapy, envisaging the validation of these biomarkers to predict response.

PATIENTS AND METHODS

DNA extracted from peripheral blood from 125 patients with bladder cancer treated with BCG therapy was analyzed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism for FAS-670 A/G and FASL-844 T/C polymorphisms. FASL mRNA expression was analyzed by real-time Polymerase Chain Reaction.

RESULTS

Carriers of FASL-844 CC genotype present a decreased recurrence-free survival after BCG treatment when compared with FASL-844 T allele carriers (mean 71.5 vs. 97.8 months, P = 0.030) and have an increased risk of BCG treatment failure (Hazard Ratio = 1.922; 95% Confidence Interval: [1.064-3.471]; P = 0.030). Multivariate analysis shows that FASL-844 T/C and therapeutics scheme are independent predictive markers of recurrence after treatment. The evaluation of FASL gene mRNA levels demonstrated that patients carrying FASL-844 CC genotype had higher FASL expression in bladder tumors (P = 0.0027). Higher FASL levels were also associated with an increased risk of recurrence after BCG treatment (Hazard Ratio = 2.833; 95% Confidence Interval: [1.012-7.929]; P = 0.047). FAS-670 A/G polymorphism analysis did not reveal any association with BCG therapy outcome.

CONCLUSIONS

Our results suggest that analysis of FASL-844 T/C, but not FAS-670 A/G polymorphisms, may be used as a predictive marker of response to BCG immunotherapy.

RNA-binding proteins in Mendelian disease

RNA-binding proteins (RBPs) control all aspects of RNA fate, and defects in their function underlie a broad spectrum of human pathologies. We focus here on two recent studies that uncovered the in vivo mRNA interactomes of human cells, jointly implicating over 1100 proteins in RNA binding. Surprisingly, over 350 of these RBPs had no prior RNA binding-related annotation or domain homology. The datasets also contain many proteins that, when mutated, cause Mendelian diseases, prominently neurological, sensory, and muscular disorders and cancers. Disease mutations in these proteins occur throughout their domain architectures and many are found in non-classical RNA-binding domains and in disordered regions. In some cases, mutations might cause disease through perturbing previously unknown RNA-related protein functions. These studies have thus expanded our knowledge of RBPs and their role in genetic diseases. We also expect that mRNA interactome capture approaches will aid further exploration of RNA systems biology in varied physiological and pathophysiological settings.

FAS-670A/G single nucleotide polymorphism may be associated with human T lymphotropic virus-1 infection and clinical evolution to TSP/HAM

FAS and FASLG genes are closely linked to the apoptosis mechanism of the immune system and several polymorphisms in these genes have been associated with susceptibility to diseases. The present study investigated the polymorphisms at positions -670 in the FAS gene, and -169 and -124 in the FASLG gene, among HTLV-1 infected subjects. Blood samples from HTLV infected subjects and seronegative individuals were collected, and polymorphisms were analyzed using a polymerase chain reaction (PCR) followed by RFLP analysis using restriction endonucleases. The genotype frequencies of the FAS -670 polymorphism was the only one that showed a higher and significant prevalence of genotype -670GG among HTLV-1 infected subjects as compared to the control group (p=0.0160), but the genotype -670AA was more frequent among TSP/HAM patients as compared to the asymptomatic individuals (p=0.0005). TCD4(+) and TCD8(+) lymphocyte counts from HTLV infected and seronegative subjects, as well as the proviral load values, according to the status of symptomatic and asymptomatic infection carrying different genotypes were compared but showed no statistical significance. The present results suggest that FAS -670 polymorphism seems to be associated with susceptibility to HTLV-1 and may increase the chance to develop TSP/HAM among HTLV-1 infected persons.

Functional polymorphisms in cell death pathway genes FAS and FAS ligand and risk of prostate cancer in a Chinese population

BACKGROUND

Apoptosis is the physiological mechanism of programmed cell death and abnormal regulation of this pathway can lead to carcinogenesis. We hypothesized that the FAS -1377G>A, -670A>G, and FASL -844T>C polymorphisms are associated with risk of prostate cancer (PCa).

MATERIALS AND METHODS

We genotyped polymorphisms in a hospital-based case-control study of 602 patients diagnosed with PCa and 703 cancer-free controls in a Chinese population using polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

We found a significantly decreased risk associated with FAS -1377GA [adjusted odds ratio (OR) = 0.71, 95% confidence interval (CI) = 0.56-0.90] genotype compared with the -1377GG genotype and decreased risk associated with FAS -670AG and -670GG genotypes (OR 0.75, 95% CI: 0.59-0.95; OR 0.70, 95% CI: 0.50-0.96) compared with the -670AA genotype. Consistently, we found that individuals carrying haplotype genotype with 0 or 1 risk allele (-1377G and -670A) had a lower risk of PCa than those with two risk alleles (OR 0.48, 95% CI: 0.28-0.80; OR 0.60, 95% CI: 0.41-0.87; OR 0.82, 95% CI: 0.69-0.97 for the AA, GG, and AG haplotype, respectively). In addition, when we evaluated these two FAS polymorphisms together, we found that the combined genotype with 4 risk alleles was associated with a significantly increased risk of PCa compared with those with 0-3 variants (OR 1.51, 95% CI: 1.19-1.91), and this increased risk was more pronounced among subgroups of Gleason score <7 and >7, and PSA > 20 ng/ml (OR 1.49, 95% CI: 1.08-2.04; OR 1.72, 95% CI: 1.25-2.44; OR 1.61, 95% CI: 1.23-2.13, respectively).

CONCLUSIONS

These results suggested that the FAS polymorphisms may contribute to PCa risk in a Chinese population.

Polymorphisms in promoter region of FAS and FASL gene and risk of cardia gastric adenocarcinoma

BACKGROUND AND AIM

The FAS and FASL system play an important role in regulating apoptotic cell death. This study was designed to investigate the correlation of FAS-1377 G/A, -670 A/G and FASL-844 T/C polymorphisms with susceptibility to gastric cardiac adenocarcinoma in a population of a high-incidence region of Hebei Province.

METHODS

FAS-1377 G/A, -670 A/G and FASL-844 T/C polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis in 262 gastric cardiac carcinoma (GCA) patients and 524 healthy controls.

RESULTS

Family history of upper gastrointestinal cancer (UGIC) might increase the risk of developing GCA (age- and sex-adjusted odds ratio [OR] = 1.38, 95% confidence interval [CI] = 1.02-1.86). The overall allelotype and genotype distributions of FAS-1377 G/A, and FASL-844 T/C polymorphisms in GCA patients did not significantly differ from that in healthy controls (P > 0.05). Compared with individuals with a FAS-670 A/A genotype, individuals with an A/G genotype in a smoker group had a lower risk of developing GCA (age, sex, and family history of UGIC adjusted OR = 0.55, 95% CI = 0.34-0.88). When the genotypes of FAS and FASL single nucleotide polymorphisms (SNP) were combined to analyze, no significant correlation was found between these SNP and the risk for GCA development.

CONCLUSION

In the high-incidence region of Hebei Province, FAS-1377 G/A and FASL-844 T/C polymorphisms were not associated with the risk of GCA. However, the FAS-670 A/G genotype might decrease the risk of GCA for smoker individuals.

A common hereditary single-nucleotide polymorphism in the gene of FAS and colorectal cancer survival

Apoptosis plays an important role in embryogenesis, autoimmunity and tumourigenesis. Cell surface death receptors such as TNFRSF6 (FAS) confer a major apoptotic effect. A single-nucleotide polymorphism in the FAS promoter gene, −670A/G, modulates apoptotic signalling and has been related to susceptibility and progression of a variety of cancers. The present study aimed to evaluate the role of this polymorphism for survival of patients with colorectal cancer. We performed a retrospective analysis including 433 patients with histologically confirmed colorectal cancer. A Cox regression model including FAS -670 genotypes, age at diagnosis, tumour grading, primary tumour size, number of lymph nodes examined, number of metastatic lymph nodes, tumour stage and application of fluorouracil-based adjuvant chemotherapy was used to estimate the effect of the FAS genotype on survival. FAS −670A/G genotype frequencies were 24.2% (AA), 46.3% (AG) and 29.5% (GG). Forty-nine patients were excluded from the Cox regression analysis because of missing values. Out of the remaining 384 patients, 69 (18%) died during a follow-up of maximum 10 years. Mean follow-up time was 58 ± 34 months (median 55 months). Carriers of the homozygous FAS -670GG genotype had a significantly lower survival rate compared with AA/AG genotype carriers (relative risk 1.76, 95% confidence interval 1.08–2.87; P= 0.023). The FAS −670A/G polymorphism may be associated with overall survival time of patients with colorectal cancer.