ESR1 and breast carcinoma: The TBCRC 006 trial (18), a single-arm phase II study, is a clinical trial of neoadjuvant lapatinib and trastuzumab with hormonal therapy and without chemotherapy in patients with HER2-overexpressing breast cancer using only the two anti-HER2 agents [combined with hormonal therapy, in the case of the ER (+) subjects].