DNMT1 and colorectal carcinoma: An influence from altered methylation was suggested by the concomitant decrease of the two DNA methyltransferases Dnmt1 and Dnmt3b. Changes in methylation accomplished by exposure of CRC cells to the demethylating agent DAC modulated their expression of endothelin system genes at RNA level when using low concentrations, which were continued for 3 days, at minimal cytotoxic side effects.