ESR1 and breast cancer: We therefore silenced OPA1 by siRNA in three other breast cancer cells that differ for histology, receptor and P53 status: T47D and MCF7, two Luminal-A ER+/PR+/HER2−/wild-type P53 cell lines; and HS578T, a Basal ER−/PR−/HER2−/wild-type P53 cell line (Fig. 2l).