tumor-infiltrating lymphocytes
Also written as: TIL — tumor-infiltrating lymphocytes
Immune cells present within and around breast tumor tissue that may indicate immune response and predict treatment outcomes.
Full Definition
Tumor-infiltrating lymphocytes (TILs) are immune cells, primarily T-lymphocytes, that migrate into tumor tissue and represent the host immune response to cancer. In breast cancer, TIL assessment involves evaluating the percentage of lymphocytes within the tumor stroma on histological examination. Higher TIL levels are associated with better prognosis in triple-negative and HER2-positive breast cancers and may predict response to chemotherapy and immunotherapy. TIL evaluation is becoming increasingly important in clinical practice as a prognostic biomarker and potential predictor of treatment response, particularly in the context of emerging immunotherapy approaches.
Usage
Usage note: Commonly abbreviated as TILs (plural) in pathology and clinical documentation.
In Context
- "High tumor-infiltrating lymphocytes (60%) in this triple-negative breast cancer suggest favorable prognosis." — Pathology report
- "Tumor-infiltrating lymphocytes assessment should be performed on all core biopsies per protocol." — Clinical trial guidelines