Although monarchE also included patients with a Ki67 < 20% but high risk clinicopathological factors (involvement of ≥3 lymph nodes, histologic grade 3 or tumor size ≥ 5 cm), the FDA approved abemaciclib in combination with endocrine therapy for node-positive, early breast cancer at high risk of recurrence only if the Ki67 is at least 20%. Here, MKI67 is linked to breast cancer.