ABCB1 and neoplasm: The acetylation of lysine open the chromatin structure, and deacetylation of this unit (lysine) cause the chromatin compaction and the stability of them, these mechanisms regulate the gene expression.50 For example, the tumor suppressor genes often silenced by methylation, in contrast, the hyper-methylation of oncogenes induced their expression.59 Demethylation of multi-drug resistance gene (MDR1), in the cancer cell lines, leads to the acquisition of multi drug-resistant phenotype and reduces the accumulation of the anti-tumor drug inside the cancer cells.