TWIST1 and cancer: Secondly, although our data convincingly indicate that DNA 5mC demethylation activity of DNMT3A regulates the hypoxia-induced EMT program in cancer cells by direct demethylation of EMT gene promoters including TWIST1 and SNAIL1, the involvement of other signaling pathway(s) mediated by this DNA demethylation activity could not be ruled out at the present time.