RecurIndex Predicts Risk of Recurrence in Early-stage Luminal Breast Cancer

Inclusion Criteria: * Age ≥ 18 years old, ≤ 70 years old. * Eastern Cooperative Oncology Group (ECOG) ≤ 2. * Postoperative pathology is clearly diagnosed as invasive breast cancer. * Estrogen receptor (ER) or progesterone receptor (PR) positive, HER2 negative. * Available with Formalin-Fixed and Parrffin-Embedded (FFPE) tumor tissue. * Stage I-II patients who have received surgery (breast-conserving or mastectomy) and the pathological staging is pT1-2N0-1M0 or pT3N0M0. * The patient had not received systemic systemic treatment (including radiotherapy, chemotherapy, immunotherapy, endocrine therapy) before enrollment. * Signed an informed consent form. Exclusion Criteria: * Breast cancer patients whose clinical or pathological stage is T4, N2-3 or M1. * Known human immunodeficiency virus infection (HIV) or acquired immunodeficiency syndrome (AIDS) related diseases. * Other psychiatric disorders that may interfere with the judgment of the study results, or abnormal laboratory tests; and who, in the judgment of the investigator, are considered unfit to participate in the study. * Patients with double breast cancer. * Severe/uncontrolled intercurrent diseases/infections. * Subjects with allogeneic organ transplants requiring immunosuppressive therapy. * Hormone receptors ER and PR are negative (any detectable estrogen and progesterone receptors do not express or express \<1%) and/or HER2 overexpression/amplified by FISH detection. * Not suitable for hormone receptor modulators (e.g. tamoxifen) and adjuvant endocrine other drug therapy.