[Standardized determination of tumor-infiltrating lymphocytes in breast cancer : A prognostic marker for histological diagnosis].

Background: Tumor-infiltrating lymphocytes (TILs) have been identified as prognostic parameter in breast cancer.
Objectives: The aim of this review article is to provide an overview on the clinical and analytical validation of TILs in breast cancer.
Materials and Methods: Summary of international guidelines of the TIL working group as well as clinical and translational studies.
Results, Conclusions: Breast carcinomas with a high TIL level have an improved response to neoadjuvant chemotherapy. Triple-negative and HER2-positive carcinomas with increased TIL levels have improved survival. TILs are a new prognostic biomarker for routine histopathological diagnosis.