MKI67 and breast cancer: In the monarchE trial [20], the addition of abemaciclib for two years reduced the absolute risk of recurrence at four years by 6.4% (hazard ratio: 0.664, 95% CI: 0.578-0.762, p<0.0001) in a cohort of women with HR-positive, HER2-negative breast cancer who had either ≥4 involved LNs or one to three positive nodes with at least one of the following high-risk features: T3 tumors (greater than 5 cm of size), grade 3 histology, or Ki-67 expression ≥20%.