They also demonstrated that this allele increases the expression of MKK4. Therefore, it is plausible to assume that Nkx-2 may inhibit MKK4 expression and lead to carcinogenesis in CRC tissue; however, for the rs3809728 A>T variant, no difference in binding factors was observed in the Wei et al. report (28). This evidence concerns the gene MAP2K4 and colorectal carcinoma.