CTCFL and colonic neoplasm: To independently verify that BORIS isoforms could be activated by DNA demethylation, we analyzed their expression in four variants of the HCT116 colon cancer cell line: the parental cell line; the single knockouts (KO) of DNMT1 and DNMT3B in which DNA methylation is reduced 20% and 3%, respectively; and the double knockout of DNMT1 and DNMT3B with genomic methylation reduced by 95% [21].