Triple negative (negative for expression of estrogen receptor, progesterone receptor, and overexpression of HER2) breast cancer cell lines dervied from metastatic cancer (Cal51 and MDA-MB-231) were treated with increasing concentrations of microtubule poisons classically considered to be stabilizers (docetaxel, ixabepilone, epothilone B) or destabilizers (vinblastine, vinorelbine, eribulin). This evidence concerns the gene ESR1 and breast carcinoma.