ESR1 and neoplasm: Though unlikely that a tumor/patient will ever experience the lipid depleted conditions as in our cell culture experiments, the results nonetheless reveal some novel and important information about the activity of 27HC in ER+ BC and open the interesting question of whether factors such as lipid/cholesterol levels in circulation and the tumor microenvironment impact the prognostic significance of 27HC (CYP27A1) on clinical ER+ BC prognosis in addition to menopausal status.