Given that ENDX at 5 μM displayed promising antitumor activity in cell line models harboring activating PIK3CA mutations, which occur in nearly 40% of patients with advanced ERα+/HER2- breast cancer43 and are associated with poor survival outcomes44, further studies are ongoing to evaluate the clinical activity of ENDX therapy in breast tumors harboring PIK3CA mutations. Here, PIK3CA is linked to breast neoplasm.