MKI67 and breast cancer: Additional objectives were to describe the incidence of monarchE clinicopathological high-risk criteria (ie, without the Ki-67 index ≥20% tumor eligibility criterion, as these data are not available in SEER) [19, 20] within the HR+, HER2- EBC population in SEER, and to determine if breast cancer-specific mortality risk differed by those patients who did and did not meet monarchE clinicopathological criteria for high risk of recurrence.