TNF and colorectal carcinoma: To investigate potential correlations of TNF-α polymorphisms with the risk of CRC, 7 studies about TNF-α -238 G/A polymorphism (901 cases and 1179 controls), 20 studies about TNF-α -308 G/A polymorphism (4412 cases and 5528 controls), 5 studies about TNF-α -857 C/T polymorphism (1045 cases and 1032 controls), 2 studies about TNF-α -863 C/A polymorphism (464 cases and 464 controls) and 3 studies about TNF-α -1031 T/C polymorphism (664 cases and 664 controls) were enrolled for analyses.