Association of Interferon Gamma +874T/A Polymorphism and Leukemia Risk: A Meta-Analysis.

Interferon gamma (IFN-γ) has antitumor and antiproliferative effects, and previous studies indicated IFN-γ +874T/A (rs2430561) polymorphism were related to the risk of many types of cancer. However, the association between IFN-γ +874T/A polymorphism and leukemia risk remained controversial.We performed a comprehensive meta-analysis based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement (PRISMA). Electronic database of Embase, Pubmed, and the Cochrane Library were searched for eligible articles published up to December 13, 2015. The association between genetic polymorphisms and leukemia risk was measured by odds ratios (ORs) and its corresponding 95% confidence intervals (CIs).A total of 8 studies amounting to 420 patients and 767 control subjects were retrieved for this study. Although associations between IFN-γ +874T/A polymorphism and overall leukemia risks were lacking, decreased chronic lymphocytic leukemia (CLL) risk was detected in the allelic model (T vs A, OR=0.660, 95%CI = 0.483-0.902, P = 0.009, I = 0.0% and P = 0.863 for heterogeneity), the codominant model (TT vs AA, OR = 0.472, 95%CI = 0.247-0.902, P = 0.023, I = 0.0% and P = 0.994 for heterogeneity), and dominant model (TT + TA vs AA, OR = 0.457, 95%CI = 0.285-0.734, P = 0.001, I = 40.3% and P = 0.195 for heterogeneity) by using fixed-effect model separately. On the contrary, results indicated T carries have an increased chronic myelogenous leukemia (CML) risk in dominant model (TT + TA vs AA, OR = 1.783, 95%CI = 1.236-2.573, P = 0.002, I = 19.0% and P = 0.295 for heterogeneity).This study suggests IFN-γ +874T/A polymorphism are related to CML and CLL risk. In addition, our work also points out IFN-γ +874T/A polymorphism may play dual contrasting role in leukemia risk.