The overall data in the additive (OR = 1.14; 95%CI = 0.95–1.37; P = 0.001 for heterogeneity), dominant (OR = 1.05; 95%CI = 0.92–1.19; P = 0.001 for heterogeneity) and recessive (OR = 1.12; 95%CI = 0.99–1.27; P = 0.035 for heterogeneity) did not show a marked association of MDM2 T309G polymorphism with lung cancer risk, indicating that individuals with homozygous G allele might not have an increased lung cancer risk compared with those who carry wild-type T allele. This evidence concerns the gene MDM2 and lung cancer.