In a radioresistance model of MCF7 breast cancer cell that was exposed to 20Gy sequential irradiation, a high level of HDAC and a low level of HAT activity for the histone PTMs, H3K9ac, H3K27ac, and H3S10pK14ac, was reported in the G0/G1 and mitotic cell cycle phases (Sharda et al., 2020). Here, HDAC9 is linked to breast carcinoma.