RARB and breast cancer: Lidocaine, which was presented in time and dose dependency, could increase the demethylation of breast cancer cells, and the methylation-inhibiting effect of DAC (5-azacytidine), which is a kind of DNMTs (DNA methyltransferases), could decrease the CpG (CpG island) methylation of tumor suppressor genes—RARβ and RASSF1A, and increase the sensitivity of cisplatin to breast cancer cells (97, 98).