CTLA4 and lung cancer: In the present meta-analysis, the combined results of all analyses showed that the pooled OR of nine studies was 1.037 (95%CI: 0.925-1.161, P=0.536) for the dominant model, 0.968 (95%CI: 0.888-1.055, P=0.456) for the recessive model, 0.992 (95%CI: 0.933-1.054, P=0.787) for the allele model, 0.980 (95%CI: 0.857-1.121, P=0.767) for the homozygote model and 1.023 (95%CI: 0.906-1.154, P=0.761) for the heterozygote model, indicating no significant association between CTLA-4 +49 A/G mutation and lung cancer susceptibility (Fig 2 A-E).