MKI67 and neoplasm: Ki67, The primary outcome is the difference in proliferation rate of Ki67 in the tumor (expressed as the percentage of tumor cells expressing Ki67). Ki67 will be measured on the original core biopsy (pretreatment) and on the lumpectomy/mastectomy specimen (posttreatment)., From time of initial biopsy to the final surgery, which is on average 4 wk