IL18 and cancer: In a stratified analysis by specific cancer types, -607C/A polymorphisms in IL-18 gene promoter was significantly associated with an increased risk of nasopharyngeal carcinoma (CA vs CC:OR =1.330, 95% CI: 1.029,1.719; Pheterogeneity=0.704; AA/CA vs. CC:OR =1.323, 95% CI: 1.037,1.687; Pheterogeneity=0.823) and esophageal cancer(CA vs CC:OR =1.371, 95% CI: 1.045,1.800; Pheterogeneity=0.528; AA/CA vs. CC:OR =1.289, 95% CI: 1.002,1.658; Pheterogeneity=0.700) in the heterozygous model and dominant model.