It has been reported that TSA can activate certain hypermethylated genes, including CDKN2B, CDKN2A, MLH1 and TIMP3 in colon cancer cells after Dnmt1 inhibition by DNA demethylating agent such as 5-aza-dc (Cameron et al., 1999). The gene discussed is MLH1; the disease is malignant colon neoplasm.