MKI67 and neoplasm: The monarchE phase III clinical trial studied the impact of a high Ki-67 PI on disease recurrence in a cohort of patients with HR+/HER2− node-positive breast cancer with high-risk clinicopathological features (at least 4 positive lymph nodes, or 1 to 3 positive lymph nodes with either tumor size ≥ 5 cm or histological grade 3 disease).