Interestingly, a recent epigenetic study demonstrated that major histone-modifying enzymes, such as HDAC2, EZH2, and PRMT5, are significantly downregulated in doxorubicin-resistant MCF7 cells [25], suggesting that downregulation or loss of certain regulators in chromatic remodeling may also play an important role in promoting the development of cancer drug resistance. This evidence concerns the gene HDAC2 and cancer.