On the contrary, we observed that 22Rv1 (IC50: 0.720 μM) was more sensitive to RGFP966 compared with C4‐2 (IC50: 1.19 μM) (Fig 7C), indicating that PTEN status is a potential determinant of the efficacy of HDAC3 inhibitor in prostate cancer treatment. This evidence concerns the gene PTEN and Familial prostate cancer.