In our in vitro system, neither CLA at 40 μM, Tam nor E2 caused considerable changes of cell growth or apoptosis in the ERα(-) human breast cancer cell line, MDA-MB-231, (Figs. 2A and 2B) or ERα(-) human primary cultured normal breast epithelial cells (ERα(-) NEC) (Figs. 2C, D and 2E). Here, ESR1 is linked to breast cancer.