Therefore, combinatorial therapies of HDACIs with inhibitors of different molecular targets/signaling, including aromatase, proteasomes, epigenetic modifiers, immune molecules, and checkpoints, with less toxicity and higher tolerability, connecting the effective suppression of intra-tumoral E2 synthesis for hormone-sensitive BC or other relevant cancers, could be effective and beneficial for the prevention and/or treatment of this life-threatening disease of women globally. This evidence concerns the gene CYP19A1 and cancer.