ESR1 and breast cancer: With the knowledge that BimEL can affect death in ER+ breast cancer cells treated with antiestrogens, it is interesting to speculate that the overexpression of Bcl2 that has been identified in antiestrogen-resistant sublines and breast cancers [61] may be selected, in part, by the cancer cell survival being dependent on blocking the cytotoxic action of BimEL, as Bcl2 binding to BimEL can abrogate the BimEL ability to induce apoptosis [62].