ESR1 and breast cancer: In contrary, Yi et al. [82] reported that SAHA enhances ERα degradation through C-terminus of Hsp70-interacting protein (CHIP)-mediated proteasomal pathway in MCF7 cells, an ER-positive breast cancer cell line and thus can be postulated that opposing effects of SAHA in different breast cancer cells could be due to the cell lines used, however precise mechanisms are yet to be identified.