Abstract
BACKGROUND/AIM: In women, breast cancer is the most commonly diagnosed cancer type and at the same time the main cause of cancer-related death. Many mechanisms are involved in the tumor microenvironment to restrict the anti-tumor activity by the immune system. Identification of novel prognostic tools based on immunological data could make significant impact in developing innovative immunotherapy strategies that will restore the anti-tumor immune system efficacy. PATIENTS AND METHODS: The study was performed on patients diagnosed with breast cancer, who were divided into two groups depending on the expression of HER2. For the studied group, first we described the infiltrate inflammatory on slides stained with haematoxylin eosin (HE) and in the second part we used flow cytometry in order to measure the percentage of T lymphocytes from the peripheral blood before and after breast cancer treatment. RESULTS: High presence of tumor-infiltrating lymphocytes (TILs) was associated with prognostic improvement, better disease-free survival, distant disease-free survival and overall survival. In breast cancer, the presence of TILs predicts the full pathological response rate (pCR) after neoadjuvant chemotherapy. TILs are one of the best examples of the strict relationship existing between natural defence and carcinogenesis. CONCLUSION: Modulation of the immune system is a promising strategy in the treatment of breast cancer, especially in triple-negative and HER2-positive molecular subtypes, the most immunogenic subtypes with a poor prognosis.