Polymorphisms of the FAS and FASL genes and risk of breast cancer

Prolactin-induced protein (PIP) increases the sensitivity of breast cancer cells to drug-induced apoptosis

We have previously shown that high expression of prolactin-induced protein (PIP) correlates with the response of breast cancer (BC) patients to standard adjuvant chemotherapy (doxorubicin and cyclophosphamide), which suggests that the absence of this glycoprotein is associated with resistance of tumor cells to chemotherapy. Therefore, in the present study, we analyzed the impact of PIP expression on resistance of BC cells to anti-cancer drugs and its biological role in BC progression. Expression of PIP and apoptotic genes in BC cell lines was analyzed using real-time PCR and Western blotting. PIP was detected in BC tissue specimens using immunohistochemistry. The tumorigenicity of cancer cells was analyzed by the in vivo tumor growth assay. Apoptotic cells were detected based on caspase-3 activation, Annexin V binding and TUNEL assay. The interaction of PIP with BC cells was analyzed using flow cytometry. Using two cellular models of BC (i.e. T47D cells with the knockdown of the PIP gene and MDA-MB-231 cells overexpressing PIP), we found that high expression of PIP resulted in (1) increased sensitivity of BC cells to apoptosis induced by doxorubicin (DOX), 4-hydroperoxycyclophosphamide (4-HC), and paclitaxel (PAX), and (2) improved efficacy of anti-cancer therapy with DOX in the xenograft mice model. Accordingly, a clinical study revealed that BC patients with higher PIP expression were characterized by longer 5-year overall survival and disease-free survival. Subsequent studies showed that PIP up-regulated the expression of the following pro-apoptotic genes: CRADD, DAPK1, FASLG, CD40 and BNIP2. This pro-apoptotic activity is mediated by secreted PIP and most probably involves the specific surface receptor. This study demonstrates that a high expression level of PIP sensitizes BC cells to anti-cancer drugs. Increased sensitivity to chemotherapy is the result of pro-apoptotic activity of PIP, which is evidenced by up-regulation of specific pro-apoptotic genes. As high expression of PIP significantly correlated with a better response of patients to anti-cancer drugs, this glycoprotein can be a marker for the prognostic evaluation of adjuvant chemotherapy.

Genetics of Immune Dysregulation and Cancer Predisposition: Two Sides of the Same Coin

Approximately 10% of cancers have a hereditary predisposition. However, no genetic diagnosis is available in 60%-80% of familial cancers. In some of these families, immune dysregulation-mediated disease is frequent. The immune system plays a critical role in identifying and eliminating tumors; thus, dysregulation of the immune system can increase the risk of developing cancer. This review focuses on some of the genes involved in immune dysregulation the promote the risk for cancer. Genetic counseling for patients with cancer currently focuses on known genes that raise the risk of cancer. In missing hereditary familial cases, the history family of immune dysregulation should be recorded, and genes related to the immune system should be analyzed in relevant families. On the other hand, patients with immune disorders diagnosed with a pathogenic mutation in an immune regulatory gene may have an increased risk of cancer. Therefore, those patients need to be under surveillance for cancer. Gene panel and exome sequencing are currently standard methods for genetic diagnosis, providing an excellent opportunity to jointly test cancer and immune genes.

Combined photodynamic therapy with chloroaluminum phthalocyanine and doxorubicin nanoemulsions in breast cancer model

Breast cancer is the most common neoplasm among women but thanks to innovative therapies, patients' prognosis has considerably improved. In this aspect, nanotechnology has been applied for cancer therapy aiming to reduce its usual side effects. In this study we aimed to evaluate the effects of nanoemulsions containing photosensitizer and chemotherapeutic agents associated with photodynamic therapy in a breast cancer in vivo model. Our results showed that synergistic treatments in which chloroaluminum phthalocyanine (NE-Pc) administered together with Doxorubicin (Dox) in the presence of laser irradiation (NE-PcDoxo + PDT) led to a reduction of 4 T1 induced breast cancer in mice, decline of tumor VEGF expression, increase in Caspase-3 expression, tissue necrosis and massive decrease in proliferative cells, as shown by Ki67 immunostaining. Furthermore, this associated treatment induced overexpression of apoptotic genes ABL1, CD70, CRADD, FASL, and NME5 and a reduction in expression of anticancer drug target genes CDK2, ERBB2, FIGF, IGF2, PARP4 and PGR. These results validate this treatment as a promising alternative to improve the currently applied anticancer strategies.

Identification of a FAS/FASL haplotype associated with endometriosis in Iranian patients

Risk factors for ovarian cancer include a number of genetic variants as well as endometriosis. The FAS-FASL system is one of the apoptotic pathways that play an essential role in the apoptotic process within the endometrium. Here, we evaluate the correlation between FAS-FASL polymorphisms with the risk of endometriosis in Iranian patients and healthy controls. We extracted DNA from whole blood samples using a DNA Purification Kit. Using the PCR-RFLP method, three SNPs, including FAS (-670 A/G) and FASL (-844 C/T and _124G/A) genes, were genotyped in 112 patients with endometriosis as well as 110 healthy controls. The frequency of genotypes and the alleles of these SNPs were analyzed by the chi-squared test for the significant association. Haplotype analysis was done by the PLINK software. The frequency distribution of haplotypes was significant between SNPs so that the ACG haplotype was more frequent in the cases than in the controls (p = .017). These results indicate that haplotype analysis can be useful for SNP analysis. The ACG haplotypes in FAS-670A/G, FASL-844C/T, and _124G/A genes may be correlated with the progression of endometriosis.

Correlation between FAS single nucleotide polymorphisms and breast carcinoma susceptibility in Asia

BACKGROUND

FAS cell surface death receptor (FAS) gene has 2 common single nucleotide polymorphisms (SNPs) in its promoter, FAS-1377G > A (rs2234767) and FAS-670A > G (rs1800682). Several studies have investigated the role of these 2 polymorphisms in etiology of breast cancer in Asian population while the outcomes are inconsistent. To derive a more precise assessment of the association between breast cancer susceptibility with FAS gene promoter SNPs, a meta-analysis of published studies was performed.

MATERIAL AND METHODS

We systematically searched PubMed, Embase, Web of Science, and the Chinese biomedical database (CBM) for papers published until November 1, 2018. Odds ratio (OR) with 95% confidential interval (95%CI) was conducted to evaluate the associations. Statistical analysis was conducted using Stata13.0 software. A total of 8 studies covering 2564 cases and 2633 controls were included.

RESULTS

The integrated results suggest the following: For the FAS-1377G/A polymorphism, we only found significant associations for allele G vs allele A (OR = 1.100, 95%CI = 1.004-1.206, P = .040). After stratification by ethnicity, a significant association was observed only for the AA+GA vs GG genotype in East Asian populations (OR = 1.177, 95% CI = 1.010-1.371, P = .037). The association was not found in West Asian populations. For the FAS -670A/G polymorphism, no association with cancer risk was found in any comparison model. Sensitivity analysis suggests that the meta-analysis results obtained after excluding any single study were similar to the original ones, suggesting that the meta-analysis results were not significantly affected by any single study.

CONCLUSION

These results indicated that FAS-1377G/A polymorphism may contribute to the increased breast cancer susceptibility and could be a promising target for cancer risk prediction. Further studies are needed to determine if the FAS gene confers a risk of breast cancer in other ethnic groups, such as Africans and Latin Americans.

Allicin induces apoptosis through activation of both intrinsic and extrinsic pathways in glioma cells

Allicin is an extract purified from Allium sativum (garlic), and previous research has indicated that Allicin has an inhibitory effect on many kinds of tumor cells. The aim of the present study was to explore the anticancer activity of Allicin on human glioma cells and investigate the underlying mechanism. MTT and colony-formation assays were performed to detect glioma cell proliferation, and explore the effect of Allicin at various doses and time-points. The apoptosis of glioma cells was measured by fluorescence microscopy with Hoechst 33258 staining, and then flow cytometry was used to analyzed changes in glioma cell apoptosis. Reverse transcription‑quantitative polymerase chain reaction and western blot analysis were used to detect the effect of Allicin on the expression levels of Fas/Fas ligand (FasL), caspase‑3, B‑cell lymphoma 2 and Bcl‑2‑associated X protein. Allicin suppressed the proliferation and colony formation ability of U251 cells in a dose‑ and time‑dependent manner. A cytotoxic effect of Allicin was observed in glioma cells in a dose‑dependent manner. Changes in nuclear morphology were observed in U251 cells with Hoechst 33258 staining. The activity of caspases were significantly elevated and Fas/FasL expression levels were increased following treatment with Allicin, at both the mRNA and protein level. These results demonstrated that Allicin suppresses proliferation and induces glioma cell apoptosis in vitro. Both intrinsic mitochondrial and extrinsic Fas/FasL‑mediated pathways react in glioma cell after treating with Allicin, which then activate major apoptotic cascades. These results implicate Allicin as a novel antitumor agent in treating glioma.

Fas and Fas ligand gene polymorphisms in Turkish patients with Familial Mediterranean Fever

Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disorder characterized by recurrent fever, serositis, abdominal pain, arthritis, arthralgia and erysipelas like erythema. Fas and Fas ligand molecules play a central role in the apoptosis signaling of various cell types including neutrophils. Neutrophils are the major cell population involved in acute inflammation in patients with FMF and the role of Fas and Fas ligand molecules in this cells of FMF patients may be crucial. Therefore, in the present study, we aimed to investigate whether the Fas cell surface receptor gene (FAS); NM_000043.5: c.-671A>G (rs1800682, MvaI) and Fas ligand gene (FASLG), NM_000639.2: c.-844C>T (rs763110, BsrD1) functional polymorphisms in patients with FMF and their relation to the main clinical features of the disease. The polymorphisms in the promoter regions of FAS c.-671A>G and FASLG c.-844C>T were investigated in 97 non-related FMF patients and 70 non-related healthy controls by using PCR-RFLP technique. The frequencies of FAS c-671AG genotype and G allele were not significantly different between FMF patients and healthy subjects. The frequency of FASLG -844TC genotype was found significantly different between the patients with FMF and healthy controls whereas T or C allele frequency was not significantly different between the groups. Haplotype frequencies of the studied polymorphisms were also not significantly different between FMF patients and controls. There were no correlations between the studied FAS c.-671A>G and FASLG c.-844C>T polymorphisms and the main clinical features of FMF such as fever, arthritis, abdominal and chest pain, arthralgia and erysipelas-like erythema. Our findings suggest that FAS c.-671AG genotype or G allele and FASLG c.-844 allele are not to be a risk factor, whereas FASLG c.-844TC genotype may be protective in the studied Turkish population. According to our results we may suggest that although not statistically significant, higher frequencies of FASLG c.-844CC genotype in FMF patients may be related to delayed apoptosis of neutrophils and ultimately cause neutrophilic inflammation by increasing FASLG expression.

DGCA: A comprehensive R package for Differential Gene Correlation Analysis

BACKGROUND

Dissecting the regulatory relationships between genes is a critical step towards building accurate predictive models of biological systems. A powerful approach towards this end is to systematically study the differences in correlation between gene pairs in more than one distinct condition.

RESULTS

In this study we develop an R package, DGCA (for Differential Gene Correlation Analysis), which offers a suite of tools for computing and analyzing differential correlations between gene pairs across multiple conditions. To minimize parametric assumptions, DGCA computes empirical p-values via permutation testing. To understand differential correlations at a systems level, DGCA performs higher-order analyses such as measuring the average difference in correlation and multiscale clustering analysis of differential correlation networks. Through a simulation study, we show that the straightforward z-score based method that DGCA employs significantly outperforms the existing alternative methods for calculating differential correlation. Application of DGCA to the TCGA RNA-seq data in breast cancer not only identifies key changes in the regulatory relationships between TP53 and PTEN and their target genes in the presence of inactivating mutations, but also reveals an immune-related differential correlation module that is specific to triple negative breast cancer (TNBC).

CONCLUSIONS

DGCA is an R package for systematically assessing the difference in gene-gene regulatory relationships under different conditions. This user-friendly, effective, and comprehensive software tool will greatly facilitate the application of differential correlation analysis in many biological studies and thus will help identification of novel signaling pathways, biomarkers, and targets in complex biological systems and diseases.

Distinct role of the Fas rs1800682 and FasL rs763110 polymorphisms in determining the risk of breast cancer among Han Chinese females

Background

In recent years, studies have demonstrated that polymorphisms in the promoters of Fas and FasL are significantly associated with breast cancer risk. However, the results of these studies were inconsistent. This case–control study was performed to explore the associations between Fas rs1800682 and FasL rs763110 polymorphisms and breast cancer.

Materials and methods

A hospital-based case–control study of 560 Han Chinese females with breast cancer (583 controls) was conducted. The MassARRAY system was used to search for a possible association between the disease risk and the two single nucleotide polymorphisms, Fas rs1800682 and FasL rs763110. Statistical analyses were performed using SNPStats software to conduct Pearson’s chi-square tests in five different genetic models. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated after adjustment to age and body mass index. PHASE v2.1 software was used to reconstruct all common haplotypes.

Results

A statistically significant association was found between Fas rs1800682 and increased breast cancer risk (AG vs AA: OR =1.37, 95% CI =1.06–1.78; AA+AG vs GG: OR =1.32, 95% CI =1.04–1.66), and also it was found that the FasL rs763110 polymorphism may decrease the risk. Stratified analyses demonstrated that the rs763110 polymorphism was associated with lower breast cancer risk among postmenopausal females (heterozygote model: OR =0.69, 95% CI =0.49–0.97; dominant model: OR =0.70, 95% CI =0.51–0.96). The T allele of rs763110 was also associated with a decreased risk of lymph node metastasis (allele model: OR =0.75, 95% CI =0.57–0.97) and an increased risk of the breast cancer being human epidermal growth factor receptor 2 positive (allele model: OR =1.37, 95% CI =1.03–1.18). Moreover, haplotype analysis showed that A_rs1800682T_rs763110 was associated to a statistically significant degree with lower risk of breast cancer (OR =0.70, 95% CI =0.53–0.91).

Conclusion

These data suggest that the presence of Fas rs1800683 is an important risk factor for breast cancer, whereas FasL rs763110 may exert a protective effect against the onset of breast cancer.

Apoptosis-Mediated Chemoprevention by Different Ratios of Fish Oil in Experimental Colon Carcinogenesis

Apoptosis plays an important role in prevention of colon cancer. In the present study, different ratios of fish oil and corn oil increased Fas expression in both phases and a decrease in FasL expression only in post initiation phase. Treatment with fish oil activated the intrinsic apoptotic pathway by increasing Bax expression and Cyt c release and decreasing Bcl-2 levels in both phases. This suggests that intrinsic pathway is upregulated by fish oil; however, Fas-FasL activity may be involved in inhibition of reversal of immune surveillance in tumor cells.

Quantitative assessment of the association between Fas/FasL gene polymorphism and susceptibility to esophageal carcinoma in a north Chinese population

The case–control study aims to investigate the association of Fas and FasL genetic polymorphisms (Fas‐670A/G (rs1800682), Fas‐1377G/A (rs2234767) and FasL‐844T/C (rs763110)) with esophageal carcinoma susceptibility in a north Chinese population. A total of 204 patients with esophageal carcinoma and 248 healthy controls were enrolled from Henan, China and genotyped by the polymerase chain reaction and restriction fragment length polymorphism method. There were no significant differences in distributions of their genotypes frequencies between patients and controls in Fas‐670A/G, Fas‐1377G/A and FasL‐844T/C polymorphisms (P > 0.05). Stratified analysis showed that no significant association was found between esophageal carcinoma and gene polymorphisms of Fas‐670 A/G, Fas‐1377G/A, and FasL‐844T/C (P > 0.05). Genetic polymorphisms in the death pathway genes Fas and FasL were not associated with risk of developing esophageal carcinoma in a north Chinese population.

Fas-670A>G polymorphism is not associated with an increased risk of acute myeloid leukemia development

The association between the increased risk of acute myeloid leukemia (AML) and Fas promoter polymorphisms has been reported previously; however, the results are inconclusive. The present study performed one case-control study to investigate the association, and a total of 98 AML patients and 2,014 healthy controls were genotyped. The data showed that the distribution of Fas-670AA, GA and GG genotypes among the AML patients were not significantly different from those of the healthy controls, all P>0.05. Following this a sub-study was conducted to analyze individuals who neither smoked nor drank. The results demonstrated that there was still no significant association between the Fas-670 polymorphism and risk of AML development, all P>0.05. Furthermore, in order to address a more accurate estimation of the association, a meta-analysis was conducted. Data were systematically collected from the Pubmed, EMBASE and the Wanfang Library. A total of 3 studies were included in this meta-analysis, which contained 1,144 AML cases and 3,806 controls. No significant association was detected between the Fas-670A>G polymorphism and AML risk [GA+GG vs. AA: odds ratio (OR) 0.93; 95% confidence interval (CI), 0.79–1.09; GG vs. AA: OR, 1.01; 95% CI, 0.82–1.24; GA vs. AA: OR, 1.12; 95% CI, 0.94–1.32; GG vs. AA+GA: OR, 0.94; 95% CI, 0.79–1.12; G vs. A: OR, 1.01; 95% CI, 0.91–1.12; all P>0.05). The analysis clearly indicated that there was no significant connection between the Fas-670A>G polymorphism and the increased risk of AML.

Significant association between FasL gene -844T/C polymorphism and risk to hepatocellular carcinoma in Egyptian patients

Fas/Fas ligand (FasL) system is the most critical apoptotic signaling entity in the extrinsic apoptotic pathway; hence mutations affecting this pathway may prevent the immune system from the removal of newly-formed tumor cells, and thus lead to tumor formation. The present study investigated the association between the FasL -844T/C polymorphism and the risk of hepatocellular carcinoma (HCC) in a cohort of Egyptian patients and explored the relationship of various clinical and pathological parameters with this single nucleotide polymorphism (SNP). Blood samples were withdrawn from hundred HCC patients and 100 age-, sex- and ethnically matched controls. The FasL -844T/C (rs763110) gene polymorphism was typed from genomic DNA using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay. Genotype distributions and allelic frequencies between patients and control subjects showed that the TT homozygous patients were two times more likely to develop HCC (p=0.011). Also, the T allele was found to be a significant risk factor for the disease (OR 1.970, 95% CI 1.250-3.105, p=0.003). No association was detected between different parameters of the disease and the SNP. For the first time, our results suggest that the -844T/C polymorphism in the FasL gene confers risk to HCC. The alarming increase in the incidence of HCC in Egypt encourages further studies to document our results in a larger sample, and recommends more genetic studies hoping to define a genomic risk prediction specific to this cancer in our population.

Single nucleotide polymorphisms of the Fas gene are associated with papillary thyroid cancer

OBJECTIVES

Fas is the prototypic representative of the death receptor subgroup of the tumor necrosis factor (TNF) receptor family. Recently, single nucleotide polymorphisms (SNPs) of the Fas or Fas ligand (FasL) genes have been shown to be associated with an increased risk of several cancers and with the prognosis of several cancers. The objective of this study was to evaluate the association between the SNPs of the Fas and FasL genes and papillary thyroid cancer (PTC) and to assess the relationship between these SNPs and the clinicopathological characteristics of PTC.

METHODS

Five SNPs located within the two genes of Fas and FasL were genotyped using direct sequencing in 94 patients with PTC and 364 healthy controls. Genetic data were analyzed using commercially available software. And, the statistical analyses were performed according to clinicopathologic characteristics of PTC.

RESULTS

Genotyping analysis demonstrated that the intron SNP (rs1571013), promoter SNP (rs1800682) and 3'-UTR SNP (rs1468063) of Fas were significantly associated with the development of PTC. We also detected a significant difference between patients with PTC and healthy controls with respect to Fas gene allele frequencies. Furthermore, we found that the 3'-UTR SNP (rs1468063) of Fas was associated with the multifocality of cancer [dominant model, OR 0.28, p=0.028; log-additive model, OR 0.43, p=0.033].

CONCLUSION

We observed a significant association between SNPs of the Fas gene and the development of PTC. In addition, there was a significant association between a Fas SNP and the multifocality of PTC.

Association between Fas/FasL polymorphism and susceptibility to leukemia: a meta-analysis

The polymorphisms in Fas/FasL system were proposed to be associated with susceptibility to leukemia, but recent studies reported controversial findings. Hence, we performed a meta-analysis to assess the association between Fas gene polymorphisms and susceptibility to leukemia. We carried out a literature search in PubMed, Embase, Web of Science and CNKI databases for studies on the associations between Fas/FasL gene polymorphisms and susceptibility to leukemia. The associations were assessed by odds ratio (OR) together with its 95% confidence intervals (CIs). 7 literatures and 14 studies with a total of 8787 subjects were eventually included into our meta-analysis. Overall, there was no association between Fas/FasL polymorphisms and susceptibility to leukemia. In subgroup analysis by ethnicity, there was also no association between Fas/FasL polymorphisms and susceptibility to leukemia in Asians and Caucasians. In addition, there was also a significant association between Fas-1377G/A polymorphism and susceptibility to leukemia in ALL patients, the A allele seemed to be a protective factor in ALL risk. In summary, more studies with large sample size are needed to provide further evidence for association between Fas/FasL polymorphisms and susceptibility to leukemia.

The association between the SNP rs763110 and the risk of gynecological cancer: a meta-analysis

FAS and FAS ligand (FASL) are the principal genes of the apoptosis pathway, which play a vital role in the etiology of various gynecological cancers. Studies have revealed that polymorphism of FASL promoter -844C>T (rs763110) influences FASL transcription process, which involving in cancer risk. Moreover, estrogen has been proved to trigger T-cell apoptosis by up-regulating FAS/FASL system in cancer cells. However, results from the published studies on the association between FASL -844C>T polymorphism and risk of gynecological cancer are conflicting. We performed a meta-analysis based on 13 case-control studies, including a total of 6256 cancer cases and 5573 controls. We used odd ratios (ORs) with 95% confidence intervals (CIs) to assess the association strength. Overall, the FASL -844CT and TT genotypes were associated with a significantly reduced risk of gynecological cancer types in homozygote comparison (OR=0.80, 95% CI=0.64-0.99), heterozygote comparison (OR=0.81, 95% CI=0.67-0.98), and dominant model (OR=0.81, 95% CI=0.67-0.98). In the stratified analyses, we observed a similar association among Asian population (heterozygote comparison: OR=0.73, 95% CI=0.56-0.95; dominant model: OR=0.75, 95% CI=0.57-0.98) and hospital-based studies (homozygote comparison: OR=0.61, 95% CI=0.43-0.86). When stratified by cancer type, there was also a significantly lower risk of the ovarian cancer in different genetic models except the recessive one. The results suggested that the FASL -844C>T polymorphism may reduce the risk of gynecological cancer.

Association between CD95L polymorphism and cervical cancer risk: evidence from a meta-analysis

Several studies have assessed the association of CD95L polymorphism with cervical cancer risk, but the data lack the power to provide compelling evidence. In this study, we aimed to clarify the association through a meta-analysis. A comprehensive search was conducted in PubMed, Embase, and Web of Science. The fixed-effects model was used to calculate odds ratio (OR) with 95 % confidence intervals (CIs). A total of five papers with six case-control studies were derived and finally included in this meta-analysis. The overall estimate did not reveal any significant association between CD95L -844C/T polymorphism and cervical cancer risk. Subgroup analysis in Asian population indicated nonsignificant nevertheless potentially increased risk in CC genotype carriers in comparison with the carriers of CT+TT genotypes (ORCC vs. CT+TT=1.16, 95 % CI=0.99-1.36, P for heterogeneity=0.231). Based on current epidemiological studies, this meta-analysis suggests that CD95L polymorphism may not be a risk factor contributing to cervical cancer development.

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.

Association between the FAS rs2234767G/A polymorphism and cancer risk: a systematic review and meta-analysis

Abnormal regulation of apoptosis can lead to carcinogenesis. Single nucleotide polymorphisms in apoptotic genes have been associated with cancer risk, such as the FAS rs2234767G/A polymorphism, which alters transcription of the FAS promoter. Downregulation of FAS, with resultant cellular resistance to death signals, has been found in many cancers. However, the association between the FAS rs2234767G/A polymorphism and cancer risk is still controversial. Here, we performed a meta-analysis including 41 articles (44 case-control studies, 17,814 cases and 24,307 controls) identified from PubMed and Chinese language (CNKI and WanFang) databases related to cancer susceptibility and the FAS rs2234767G/A polymorphism. We used odds ratios (ORs) and 95% confidence intervals (CIs) to assess the strength of the associations. We found that the rs2234767 G-allele was a protective factor for cancer risk (GG vs. AA: OR=0.88, 95% CI=0.79-0.98; GG+GA vs. AA: OR=0.87, 95% CI=0.79-0.96). Similar associations were detected in the "source of control", ethnicity, and cancer type subgroups. Further studies on a larger sample size and considering gene-environment interactions should be conducted to confirm the role of FAS polymorphisms, especially rs2234767G/A, in cancer risk.

Association of Fas -1377 G/A polymorphism with susceptibility to cancer

BACKGROUND

The relationship between Fas -1377 G/A polymorphism and cancer susceptibility has been implicated in accumulating data. However, the data presented inconsistent results. This study was devised to investigate the association of Fas -1377 G/A polymorphism and cancer susceptibility in a large number of participants.

METHODS

The databases of PubMed, Embase, and Web of Science were searched and a total of 27 case-control studies including 13,355 cases and 16,078 controls were included in this meta-analysis. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the fixed-effects model. Statistical analyses were performed by using Stata software.

RESULTS

The results suggested that Fas -1377 G/A polymorphism was overall associated with cancer susceptibility (additive model: OR, 1.16, 95%CI = 1.06-1.27, Pheterogeneity = 0.381; recessive model: OR, 1.19, 95%CI = 1.10-1.29, Pheterogeneity= 0.137). In the subgroup analysis by cancer type, significantly increased risk was observed in breast cancer (additive model: OR, 1.24, 95%CI = 1.04-1.58, Pheterogeneity = 0.614; recessive model: OR, 1.24, 95%CI = 1.02-1.51, Pheterogeneity = 0.349) and lung cancer (recessive model: OR, 1.25, 95%CI = 1.04-1.49, Pheterogeneity = 0.090). Similarly, elevated cancer risk associated with Fas -1377 G/A polymorphism was revealed in Asians.

CONCLUSIONS

The combined results suggest that Fas -1377 G/A polymorphism might modulate cancer susceptibility in an Asian-specific manner.

FasL gene -844T/C mutation of esophageal cancer in South China and its clinical significance

In this study, we investigated the association between the FasL -844T/C polymorphism and the risk of developing esophageal squamous cell carcinoma (ESCC) in South China. For the investigation, we randomly selected 248 patients suffering from ESCC from Southern China along with 297 healthy individuals as the control group. The relationship between the FasL gene -844T/C SNP and ESCC was studied using PCR-RFLP and immunohistochemistry. The Fas -1377G/A SNP was also selected for investigation to detect whether it interferes with the functional effect of the FasL -844C/T polymorphism in ESCC development. A significant difference in the FasL -844T/C genotypes between the patients and the control group was observed (P<0.05), with those expressing the C allele having a significantly reduced risk of developing ESCC, however younger patients (<60 years) exhibited a more malignant pathological T grade if they were homozygous for the C allele. FasL -844 CC combined with the Fas -1377 G allele is a protective factor against ESCC. Having said this, even though the C allele has a protective effect prior to development of ESCC, once the host does develop the condition the tumour will develop faster and have a higher degree of malignancy than T carriers.

FASLG T844C polymorphism and susceptibility to breast cancer: a meta-analysis

Many studies were published to assess the association between FASLG T844C polymorphism and susceptibility to breast cancer, but the data were controversial. A meta-analysis was performed to assess the association comprehensively. We performed a comprehensive search in PubMed, Embase, and Web of Science to find eligible studies. Six studies with a total of 6,784 participants were finally included into the meta-analysis. There were a total of 3,382 cases with breast cancer and 3,402 controls in those six studies. Odds ratio (OR) with 95 % confidence interval (95 %CI) was used to evaluate the association. Overall, there was an obvious association between FASLG T844C polymorphism and breast cancer under all four contrast models (for C versus T: OR = 1.26, 95 %CI 1.05-1.50, P OR = 0.011; for CC versus TT: OR = 1.42, 95 %CI 1.11-1.81, P OR = 0.005; for CC versus TT/TC: OR = 1.41, 95 %CI 1.06-1.88, P OR = 0.019; for CC/TC versus TT: OR = 1.16, 95 %CI 1.01-1.33, P OR = 0.038). In the subgroup analysis by ethnicity, there was an obvious association between FASLG T844C polymorphism and breast cancer in Asians, but there was no obvious association in Caucasians. The meta-analysis suggests that there is an association between FASLG T844C polymorphism and susceptibility to breast cancer, especially in Asians.

Quantitative assessment of the association between three polymorphisms in FAS and FASL gene and breast cancer risk

FAS and FAS ligand (FASL) play crucial roles in apoptotic signaling, and deregulation of this pathway may facilitate carcinogenesis. Studies on the association between the FAS/FASL polymorphisms (FAS-1377G/A rs2234767, FAS-670A/G rs1800682, and FASL-844C/T rs763110) and breast cancer risk have reported inconsistent results. Therefore, to characterize the relationship between those polymorphisms and breast cancer risk, we undertook a meta-analysis of those studies. Several electronic databases were searched for articles on the FAS/FASL polymorphisms and breast cancer risk. The genotype data were extracted; pooled odds ratios (OR) with 95% confidence intervals (CIs) were used to estimate the strength of the association. Five studies were eligible for our meta-analysis. Overall, we observed significant associations of the FAS-1377G/A polymorphism with breast cancer susceptibility (AG vs. GG: OR = 1.15, 95% CI 1.02-1.30; AA vs. GG: OR = 1.39, 95% CI 1.12-1.72; AG/AA vs. GG: OR = 1.18, 95% CI, 1.16-1.32; A vs. G: OR = 1.16, 95% CI 1.06-1.26), but we did not observe significant association of the Fas-670A/G and FasL-844C/T polymorphisms with breast cancer risk. In the subgroup analysis, we observed that the FAS-1377G/A and FASL-844C/T polymorphisms were associated with breast cancer risk in Chinese but not Whites; we still did not observed association of the FAS-670A/G polymorphism with breast cancer risk. Our meta-analysis revealed that FAS-1377G>A polymorphism was associated with an increased risk of breast cancer. FASL-844C>T polymorphism might be associated with a reduced breast cancer risk in Chinese. However, FAS-670A/G had no any effect on breast carcinogenesis.

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 rs763110 polymorphism contributes to cancer risk: an updated meta-analysis involving 43,295 subjects

Background

Published studies investigating the association between genetic polymorphism -884C/T (rs763110) of the FAS ligand (FASL) promoter and cancer risk reported inconclusive results. To derive a more precise estimation of the relationship, we performed an updated meta-analysis of all eligible studies.

Methodology/Principal Findings

We carried out a meta-analysis, including 47 studies with 19,810 cases and 23,485 controls, to confirm a more conclusive association between the FASL rs763110 polymorphism and cancer susceptibility. Overall, significantly reduced cancer risk was associated with the variant -884T when all studies were pooled (TC vs. CC: OR = 0.83, 95%CI = 0.75–0.92; P_{heterogeneity}<0.001; TT+TC vs. CC: OR = 0.85, 95%CI = 0.77–0.94; P_{heterogeneity}<0.001). Stratified analysis revealed that there was a statistically reduced cancer risk in Asians (TC vs. CC: OR = 0.76, 95%CI = 0.67–0.87; P_{heterogeneity}<0.001; TT+TC vs. CC: OR = 0.79, 95%CI = 0.70–0.90; P_{heterogeneity}<0.001) and in patients with cancers of head and neck (TC vs. CC: OR = 0.87, 95%CI = 0.77–0.99; P_{heterogeneity} = 0.118; TT+TC vs. CC: OR = 0.88, 95%CI = 0.78–0.99; P_{heterogeneity} = 0.168) and ovarian cancer (TC vs. CC: OR = 0.67, 95%CI = 0.49–0.90; P_{heterogeneity} = 0.187; TT+TC vs. CC: OR = 0.64, 95%CI = 0.48–0.86; P_{heterogeneity} = 0.199). Meta-regression showed that ethnicity (p = 0.029) and genotyping method (p = 0.043) but not cancer types (p = 0.772), sample size (p = 0.518), or source of controls (p = 0.826) were the source of heterogeneity in heterozygote comparison.

Conclusion

Our results suggest that the FASL polymorphism rs763110 is associated with a significantly reduced risk of cancer, especially in Asian populations.

FAS-1377 G/A (rs2234767) polymorphism and cancer susceptibility: a meta-analysis of 17,858 cases and 24,311 controls

BACKGROUND AND OBJECTIVES

Disruption of apoptosis has been implicated in carcinogenesis. Specifically, various single-nucleotide polymorphisms (SNPs) in apoptotic genes, such as FAS-1377 G/A SNP, have been associated with cancer risk. FAS-1377 G/A SNP has been shown to alter FAS gene promoter transcriptional activity. Down-regulation of FAS and cell death resistance is key to many cancers, but an association between FAS-1377 G/A SNP and cancer risk is uncertain. Therefore, we conducted a meta-analysis of the current literature to clarify this relationship.

METHODOLOGY/PRINCIPAL FINDINGS

From PubMed and Chinese language (CNKI and WanFang) databases, we located articles published up to March 5, 2013, obtaining 44 case-control studies from 41 different articles containing 17,858 cases and 24,311 controls based on search criteria for cancer susceptibility related to the FAS gene -1377 G/A SNP. Odds ratios (ORs) and 95% confidence intervals (CI) revealed association strengths. Data show that the -1377 G allele was protective against cancer risk. Similar associations were detected in "source of control," ethnicity and cancer type subgroups. Lower cancer risk was found in both smokers with a GG+GA genotype and in non-smokers with the GG+GA genotype, when compared to smokers and nonsmokers with the AA genotype. Males carrying the -1377G allele (GG+GA) had lower cancer incidence than those with the AA genotype. Individuals who carried both FAS-1377(GG+GA)/FASL-844(TT+TC) genotypes appeared to have lower risk of cancer than those who carried both FAS-1377 AA/FASL-844 CC genotypes.

CONCLUSIONS/SIGNIFICANCE

The FAS-1377 G/A SNP may decrease cancer risk. Studies with larger samples to study gene-environment interactions are warranted to understand the role of FAS gene polymorphisms, especially -1377 G/A SNP, in cancer risk.

Increased resistance to Staphylococcus aureus endophthalmitis in BALB/c mice: Fas ligand is required for resolution of inflammation but not for bacterial clearance

FasL was recently shown be required for bacterial clearance in C57BL/6 mice that express the FasL.1 allotype. The FasL.2 allotype is expressed in BALB/c mice and exhibits increased binding affinity to and increased cytotoxic activity against Fas(+) target cells. Therefore, we hypothesized that BALB/c mice would be more resistant to Staphylococcus aureus-induced endophthalmitis. To test this hypothesis, C57BL/6, BALB/c, and BALB(gld) mice received intravitreal injections of 2,500 CFU of S. aureus (RN6390). Clinical examinations, electroretinography (ERG), histology, and bacterial quantification were performed at 24, 48, 72, and 96 h postinjection. The myeloperoxidase (MPO) assay was used to quantitate neutrophil infiltration. At 96 h postinfection, 86% of C57BL/6 mice presented with complete destruction of the eye, compared to only 29% of BALB/c mice with complete destruction. To our surprise, in the absence of Fas ligand, BALB(gld) mice showed no difference in bacterial clearance compared to BALB/c mice. However, histology and ERG analysis revealed increased retinal damage and significant loss of retinal function. MPO analysis revealed equal numbers of neutrophils in BALB(gld) and BALB/c mice at 24 h postinfection. However, at 48 h, the neutrophil numbers remained significantly elevated in BALB(gld) mice, correlating with the increased retinal damage observed in BALB(gld) mice. We conclude that the increased resistance to S. aureus induced endophthalmitis in BALB/c mice is not dependent upon the FasL. However, in contrast to C57BL/6 mice, FasL is required for resolution of inflammation and protecting host tissue from nonspecific damage in BALB/c mice.