FAS and FASL promoter polymorphisms and susceptibility to HBV infection: A systematic review and meta-analysis

Abstract FAS/FASL system act as a major pathway that triggers apoptosis cascade in the liver by transmitting the death signal to the target cells. In this systematic review and meta-analysis, we aimed to evaluate the relationship between major polymorphisms of FAS/FASL complex 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 meta-analysis; 5 on FASL -844 C/T (rs763110), 4 on FASL IVS2nt-124, 6 on FAS -670 A/G (rs1800682), and 4 on FAS -1377 A/G (rs2234767). Meta-analysis showed there is no statistically significant association between risk 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 risk of HBV infection. To reach a definitive conclusion, large scale studies with patients of different ethnicity are still needed.