Prognostic Impact of Regulatory T-cells in Predicting Response and Prognosis in Primary Breast Cancer

Background: The role of tumor-infiltrating lymphocytes (TILs) in breast cancer has been extensively studied over the last decade; it now believed that they have predictive and prognostic roles in breast cancer. Materials and Method: We identified 70 patients with primary breast cancers receiving neoadjuvant chemotherapy (NAC); we analyzed pre-and post-treatment tumor-infiltrating immune cells (CD3, CD8) by immunohistochemistry. Immune cell profiles were analyzed and correlated with response and survival. Results: We identified two tumor-infiltrating immune cell profiles, which were able to predict pathological complete response (pCR) to NAC. A higher infiltration by CD8 and CD3 lymphocytes was associated with occurrence of pCR. Analysis of the immune infiltrate in post-chemotherapy treatment identified a profile of high CD8 and low CD3 infiltration associated with better disease free survival. Conclusions: Tumor lymphocytic infiltrates play a predictive role for detecting pCR and a prognostic role in detecting the outcome. Further understanding of the mechanisms underlying the distribution of immune cells and their changes after chemotherapy may contribute to the development of new immune-targeted therapies for breast cancer.