Abstract: Triple-negative breast cancer (TNBC) and human epidermal growth factor receptor-2 (HER2)-positive breast cancer are the most aggressive subtypes of breast cancer with higher recurrent rates, distant metastasis rates and poor prognosis. There are increasing evidence suggesting that high level of tumor-infiltrating lymphocytes (TIL) is associated with a more favorable outcome. However, the complex cellular components within TIL have an enormous influence on the prognostic value of TIL in patients with various subtypes or patients receiving different therapies. In this review, we summarized the classification of TIL, the value of TILs in TNBC and HER2-positive breast cancer and immunotherapies related to TIL.

Key words: Tumor-infiltrating lymphocytes, Triple-negative breast cancer, HER2-positive breast cancer, Immunotherapy