Correlations Between Known Prognostic Markers and Tumor - infiltrating Lymphocytes in Breast Cancer

The presence of tumor-infiltrating lymphocytes (TILs) is associated with a favorable long-term outcome in breast cancer. The main objective of this study was to show that there is a correlation between known prognostic and predictive factors and TILs. We retrospectively identified 56 patients with human epidermal growth factor receptor-2 (HER2 +, n = 22) and HER2 negative (HER2-, n = 34) breast cancer diagnosed between 2012 and 2018 at the Institute of Oncology Prof. Dr. Alexandru Trestioreanu, Bucharest. Hematoxylin-eosin-stained slides of these paired samples were evaluated for stromal TILs. The present study reports that TILs can be used as a clinically useful biomarker that has the ability to stratify HER2 negative and HER2 positive patients in prognostic function, bringing relevant information in addition to the established prognostic factors.