In addition, this combination of epigenetic agents may also help to avoid immune evasion strategy of tumors by up-regulating the expression of the major histocompatibility complex, class-I-related, a powerful NKG2D ligand for NK cell-mediated antitumor immunity [44] as we have observed it in a colon carcinoma cell line treated with hydralazine and valproate [22]. This evidence concerns the gene KLRK1 and colon carcinoma.