In conclusion, we demonstrate that IL-18 gene promoter −607 C>A polymorphism is significantly associated with overall cancer risk, especially in nasopharyngeal carcinoma and gastrointestinal cancer; and the −137 G>C polymorphism is associated with increased overall cancer risk in Asian populations and also significantly increase the risk of nasopharyngeal carcinoma. Here, IL18 is linked to nasopharyngeal carcinoma.