MKI67 and neoplasm: When a luminal B definition based on ER-positive, PR-positive or PR-negative, Her2-positive or Her2-negative, and greater than 14% Ki67-positive tumor cells26 was used, a large number of patients with the luminal A subtype shifted to the group with the luminal B subtype across all parity groups (Figure 4A-C and eFigure 7C in the Supplement), corroborating previous findings.1,32