TNF and cancer: In our meta-analysis, 535 cases and 922 controls were enrolled and we found that TNF-a 238 polymorphism was not significantly associated with colorectal cancer risk Previously, a meta-analysis including 34 studies with 34,679 cases and 41,186 controls reported that no significant association was found between the TNF-a 238 polymorphism and the overall cancer risk [44], which is in conformity with our present results.