ESR1 and neoplasm: Significant prognostic factors for DFS were age at diagnosis; tumor size; lymph node involvement; individual ER, PgR, and HER2 statuses; p53 (0 or 1+ vs. 2+ or 3+); Ki-67 (cut-off: 20%); the type of operation (breast conserving surgery [BCS] vs. mastectomy); adjuvant hormone therapy; and intrinsic subtype (luminal A vs. non-luminal A).