This study included 5,637 patients with high-risk of relapse characteristics defined as the presence of at least 4 positive axillary lymph nodes (N +) or 1–3 N + plus one or more of the following features: tumor size of at least 5 cm, histologic grade 3 and/or high centrally determined Ki67 (≥ 20%). The gene discussed is MKI67; the disease is neoplasm.