ERBB2 and neoplasm: During the initial diagnosis, the immunohistochemistry (IHC) results from core needle biopsy found three patients with HER2-positive tumors and another three with HER2-negative tumors; however, after neo-adjuvant chemotherapy, the final IHC results from tumor excision showed two patients with HER2-positive tumors and four with HER2-negative tumors.