Nevertheless, in subgroup analysis regarding smoking status, increased lung carcinoma susceptibility was shown among the never-smoking subgroup (GG vs TT: OR = 1.76; 95%CI = 1.36–2.29; P = 0.926 for heterogeneity; dominant model: OR = 1.48; 95%CI = 1.22–1.81; P = 0.501 for heterogeneity; recessive model: OR = 1.37; 95%CI = 1.11–1.69; P = 0.994 for heterogeneity), suggesting that G allele of MDM2 might increase lung cancer risk among individuals who have no smoking history. This evidence concerns the gene MDM2 and lung cancer.