Furthermore, others have demonstrated that decitabine may reduce tumor cell sensitivity to cisplatin by reversing promoter-methylation-induced downregulation of the resistance factor glutathione-S-transferase-pi [48] and demethylating agents also increased tumor cell expression of resistance-associated drug efflux pumps, including MDR1/p-glycoprotein [49,50]. This evidence concerns the gene ABCB1 and neoplasm.