The PHERGain study evaluating de-escalating neoadjuvant therapy in patients with HER2+ breast cancer demonstrated a pCR rate of 32.3% in patients with ER+/HER2+ early breast cancer treated with neoadjuvant endocrine therapy, but with dual HER2 blockade utilizing trastuzumab, and pertuzumab21. The gene discussed is ESR1; the disease is breast carcinoma.