ESR1 and neoplasm: We investigated the efficacy of trastuzumab and pertuzumab in relation to the ER and PgR status of tumours and found a pCR rate of 64.3% (95%CI: 39–89%) in ER-positive and PgR-negative tumours compared to 31.6% (95%CI: 11–52.5%) for ER-positive and PgR-positive tumours.