ESR1 and breast cancer: The second patient with long-duration disease control had primary estrogen-receptor-positive, HER2-negative papillary carcinoma breast cancer (non-assessable grade, T4N1MX at diagnosis, based on the patient report form) with metastatic disease in a mediastinal lymph node and the liver on study entry, and had received three chemotherapeutic regimens and six hormonal therapies prior to study entry.