DNMT1 and colorectal carcinoma: Next, the CRC cell lines RKO and HCT116, which carry methylated NTRK3, were treated with 5-aza-2′-deoxycytidine (5-AZA), which inhibits DNA methyltransferase1 (DNMT1), to determine if demethylation of the NTRK3 promoter would induce NTRK3 expression.