ColXα1 and Tumor Infiltrating Lymphocytes: a Marker of Response to Neoadjuvant Therapy in Estrogen Receptor and Human Epidermal Growth Factor Receptor 2 Positive Breast Cancer

This study focused on patients with estrogen receptor positive/human epidermal growth factor receptor 2 positive (ER+/HER2+) breast cancer treated with neoadjuvant chemotherapy and HER2-targeted therapy (NAC+H), and was designed to identify novel biomarkers by correlating gene expression, histology and immunohistochemistry with pathologic response. We performed gene expression profiling on 11 pre-treatment tumors samples: 5 who had no or minimal residual disease residual cancer burden (RCB) score of 0 or 1 and 6 who had significant residual disease (RCB score of 2 or 3). ER2/HER2 postive breast tumors biopsied before neoadjuvant chemotherapy were selected to identify potential biomarkers of pathological complete response (pCR)