Breast cancer and HSP90 inhibitors: is there a role beyond the HER2-positive subtype?

HSP90 inhibitors have shown great promise as therapeutic targets because they have the potential to suppress multiple signaling pathways simultaneously, and many are currently under clinical development. Because HER2 is known to be a client protein sensitive to inhibition of the HSP90 chaperone complex, HSP90 inhibitors have been studied in HER2-positive breast cancer and have shown promising results. In this article, we revisit HSP90 inhibitors in the context of breast cancer and discuss some notable preclinical data that reveal potential roles in both hormonal receptor-positive and triple negative breast tumor subtypes.