Moreover, meta‐analyses performed using the breast cancer gene‐expression miner v3 tool (expression and correlation analysis modules) (Jézéquel et al., 2013) also showed an inverse correlation between ERα and HDAC9 expression (Fig. S2D) as well as between HDAC9 and PR expression in breast tumors (Fig. S2E). Here, HDAC9 is linked to breast neoplasm.