MET and PTEN gene copy numbers and Ki-67 protein expression associate with pathologic complete response in ERBB2- positive breast carcinoma patients treated with neoadjuvant trastuzumab-based therapy

Background Pathologic complete response (pCR) after neoadjuvant chemotherapy for breast cancer is associated with improved prognosis in aggressive tumor subtypes, including ERBB2- positive tumors. Recent adoption of pCR as a surrogate endpoint for clinical trials in early stage breast cancer in the neoadjuvant setting highlights the need for biomarkers that, alone or in combination, help predict the likelihood of response to treatment.