Cell lines were authenticated (most recent date listed [ ]) by the University of Arizona Genetics Core and mycoplasma tested (Lonza #LT07–418). Lab stocks were made following authentication and used for this study. MCF-7 (ATCC; DMEM+10% FBS [06/29/16]), T47D (ATCC; RPMI+10% FBS [02/08/17]), ZR75.1 (ATCC; RPMI+10% FBS [10/13/16]), MDA-MB-231 (ATCC; DMEM+10% FBS [10/13/16]), MDA-MB-134-VI (ATCC; 50/50 DMEM/L15+10% FBS [02/08/17]), SUM44PE (Asterand; DMEM/F12+2% CSS with 5ug/ml insulin, 1ug/ml hydrocortisone, 5mM ethanolamine, 5ug/ml transferrin, 10nM triodothyronime, and 50nM sodium selenite [02/08/17 – no reference profile exists in database]), and BCK426 (link) (MEM+5% FBS with 1nM insulin and 1× NEAA [10/13/16 – no reference profile exists in database) cells were cultured with indicated media conditions.