DNMT1 and neoplasm: DNMT inhibitor, including azacitidine, 5-aza-2′-deoxycytidine (5-Aza-Dc, decitabine), guadecitabine, hydralazine, procaine, MG98 and/or zebularine, among which 5-Aza-Dc is the most commonly used, could cause demethylating and reactivate the expression of TSGs, then suppress the metastasis of tumor cells (Cheishvili, 2015; Zhou, 2018; Katarzyna & Lucyna, 2019).