Considering the DNA demethylation is closely related to the TET family of demethylases and the DNMT family of methylases, small interfering RNA (siRNA)s (siTET1, siTET2, siTET3, siDNMT1, siDNMT3A, siDNMT3B) was transfected into targeted MDA‐MB‐231 and HCC‐1806 cells. Here, DNMT1 is linked to hepatocellular carcinoma.