HDAC4 and skin cancer: The mechanistic insights revealed a decreased methylation ratio of CpG dinucleotides in the promoter region of Nrf2 in SFN-treated skin cancer cells, and SFN also attenuated the expression of HDACs (HDAC1, HDAC2, HDAC3, and HDAC4) and DNMTs (DNMT1, DNMT3a, and DNMT3b) [42].