PKM and breast cancer: However, in another study, a 24 h treatment of MDA-MB-231 cells with BA (up to 20 μM) did not alter lactate levels nor the expression of glycolytic enzymes [25], while BA-treated SK-BR-3 and MCF-7 breast cancer cells displayed decreased protein levels of hexokinase (HK2) and/or pyruvate kinase PKM2 [24,25].