ESR1 and breast carcinoma: Here, we focused on the ER-positive BRCA patients and found that the hypo-ER-positive subgroup contains a small number of luminal B breast cancers compared with that in the hyper-ER-positive subgroup (9.8% vs. 27.4%), echoing the fact of worse survival for luminal B BRCA patients (Additional file 1: Figure S2B).