IFNG and B-cell chronic lymphocytic leukemia: 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, I2 = 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, I2 = 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, I2 = 40.3% and P = 0.195 for heterogeneity) by using fixed-effect model separately.