FAS−1377 A/G polymorphism in breast cancer: a meta-analysis

Polymorphisms in genes involved in breast cancer among Iranian patients

This review gives a summary of the important genetic polymorphisms in breast cancer with a focus on people in Iran. Several single nucleotide polymorphisms were considered as breast cancer susceptibility polymorphisms within genes (STK15, ERRs, ESR1, p53, SEP15, AURKA, SHBG, SRC, FAS, VEGF, XRCC1, GST, NFκB1, XPC, XRCC3, sirtuin-3, NKG2D). Cytosine-adenine repeat (IGF-I), rs3877899, G-2548A, GGC (eRF3a/GSPT1), IVS2nt-124A/G have shown an increased risk of breast cancers and a decreased risk has been observed in 4G/5G (PAI-1), rs6505162, tri-nucleotide (GCG TGFBR1). We observed that the signaling pathways and antioxidant related genes are the main molecular processes associated with breast cancer progression. Further studies on types of polymorphisms in breast cancer could validate the prognostic value of biomarkers.

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.

Fas and FasL promoter polymorphisms and susceptibility to HBV infection: A systematic review and meta-analysis

Apoptosis is a universal cellular defense mechanism against senescent, damaged, genetically mutated, or virally-infected cells. It also is critical for the maintenance of liver health. Fas and FasL system act as a major death pathway that triggers apoptosis cascade in the liver. In this systematic review and meta-analysis, we aimed to investigate the relationship between four major polymorphisms of Fas and FasL genes with susceptibility to or clearance of HBV infection. All the eligible studies were extracted from PubMed and Scopus with no date and language restriction. ORs with 95% CIs were used to evaluate the strength of the association based on the following genetic models: (1) the allelic, (2) the homozygote, (3) the dominant, and (4) the recessive models. Totally 7 related articles were included in this meta-analysis; 5 studies of 7 related articles investigated FasL -844C/T (rs763110) polymorphism, 4 studies investigated FasL IVS2nt-124, 6 studies investigated Fas -670 A/G (rs1800682), and 4 studies investigated Fas -1377 A/G (rs2234767) polymorphism. This meta-analysis showed that there is no statistically significant association between the risk or clearance of HBV infection and four studied Fas and FasL polymorphisms in their allelic comparison or genetic models. Fas -670, Fas -1377, FasL -124, and FasL -844 polymorphisms did not show any significant association with the clearance or risk of HBV infection. Therefore, it seems that susceptibility to HBV infection or clearance of it is not affected by Fas and FasL genetic polymorphisms. But, to reach a definitive conclusion, further studies with a larger sample size of different ethnicity are still needed.

Common shared genetic variation behind decreased risk of breast cancer in celiac disease

There is epidemiologic evidence showing that women with celiac disease have reduced risk of later developing breast cancer, however, the etiology of this association is unclear. Here, we assess the extent of genetic overlap between the two diseases. Through analyses of summary statistics on densely genotyped immunogenic regions, we show a significant genetic correlation (r = −0.17, s.e. 0.05, P < 0.001) and overlap (P_permuted < 0.001) between celiac disease and breast cancer. Using individual-level genotype data from a Swedish cohort, we find higher genetic susceptibility to celiac disease summarized by polygenic risk scores to be associated with lower breast cancer risk (OR_per-SD, 0.94, 95% CI 0.91 to 0.98). Common single nucleotide polymorphisms between the two diseases, with low P-values (P_CD < 1.00E-05, P_BC ≤ 0.05), mapped onto genes enriched for immunoregulatory and apoptotic processes. Our results suggest that the link between breast cancer and celiac disease is due to a shared polygenic variation of immune related regions, uncovering pathways which might be important for their development.

Susceptibility to oral cancers with CD95 and CD95L promoter SNPs may vary with the site and gender

We investigated risk association of oral cancers (tongue and buccal mucosa cancers) with FAS (-1377G > A and FAS -670 A > G) and FASL (-844 T > C) SNPs, in males and females. A case-control study of 535 oral cancer and 525 control subjects was performed. SNPs were detected in the genomic DNA isolated from peripheral blood using PCR-RFLP. We report FASL -844 T > C SNPs increased risk for buccal mucosa cancer in females but not in males. On the other hand, FAS genotypes did not alter the risk of the cancers in both females and males. However, co-occurrence of FAS -1377 GA and -670 GG, FAS -1377 AA and -670 GG genotypes, and combined genotypes of FAS and FASL (FAS -1377 AA + FAS -670 GG + FASL -844 CC) alter male susceptibility towards tongue cancer. In females, combined genotypes of FAS (-1377GA and -670 AA) were found to be a risk factor of buccal mucosa cancer (OR = 3.27, CI = 1.28-8.36; P ≤ 0.01). FASL variants (GA and AA) increased tongue cancer risk in females who were tobacco users compared to non-tobacco users. In conclusion, SNPs of the FAS and FASL might alter risk of tongue and buccal mucosa cancers differentially, in a gender-dependent manner.