EGCG inhibits Dnmt activity resulting in a decreased 5-methylcytosine concentration; 20 μmol/L of EGCG already inhibited Dnmt activity in oesophageal (KYSE-150), colon (HT-29), prostate (PC-3), and breast (MCF7 and MDA-MB-231) cancer cells, although no effects of EGCG on Dnmt activity (2–50 μmol/L) are also shown in cancer cells. The gene discussed is DNMT1; the disease is cancer.