ESR1 and neoplasm: The mammography and breast Ultrasound (US) showed a suspicious neoplasm of 37 × 17 mm, and the needle-biopsy demonstrated a high-grade (G3), estrogen receptor (ER)-positive (40%), progesterone receptor (PgR)-negative, Ki67 = 40%, c-erb-2 protein-positive (3+) invasive ductal breast cancer.