- Participant has operable stage I-IIIa breast cancer of the following subtypes: (1) estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and human epidermal growth factor receptor 2 (HER2)-negative breast cancer; (2) ER-positive tumor meeting one of the following criteria: histologic grade 3; histologic grade 2 and PR-negative; histologic grade 2 and Ki67 antigen ≥10%. Tumor is at least 2 cm in diameter as assessed by physical or radiographic exam