Among them, the rs3826392 (-1304 T>G) variant is sited in the promoter of the MKK4 gene and has been frequently shown as a protective genetic factor in several cancers, including CRC (24, 28, 34, 35, 37); however, the variant rs3809728 (-1044A>T), also located in the MKK4 promoter, has not been associated with any cancer (24, 28, 34, 35). This evidence concerns the gene MAP2K4 and cancer.