MKI67 and neoplasm: Of the 20 patients with potential therapy changes, 11 (22.9% of the 48 discordant patients and 6.1% of the study cohort) were recommended therapy changes due to the subtype of PT2, i.e., two patients received additional endocrine therapy due to changes in ER status, three received additional chemotherapy due to changes in Ki67 status or tumor grade, and six received additional combined chemotherapy and trastuzumab due to HER2 positivity (Fig. 2).