IGF2 and colorectal carcinoma: For instance, Rhee et al. (2002) demonstrated that DNMT1 and DNMT3B collectively maintained virtually all methylation in HCT116 cells (a cell from CRC), including the normal methylation of repeated sequences and the silencing-associated methylation genes like insulin-like growth factor 2 (IGF2), TIMP metallopeptidase inhibitor 3 (TIMP3), and p16.