To do this, we initially used the well-characterised pair of colorectal cancer cell lines HCT116 wild type (WT) and double knockout (DKO), which have high methylation levels at most loci in WT and low levels in the daughter cell line DKO due to decreased levels of DNMT1 and DNMT3B enzymes [44]. This evidence concerns the gene DNMT1 and colorectal cancer.