Prognostic and Predictive Value of Tumor-Infiltrating Lymphocytes in Breast Cancer

Recent attention has focused on the antitumor immune response in breast cancer, in particular, the role of tumor-infiltrating lymphocytes (TILs). In certain breast cancer subtypes, the presence of TILs has prognostic value and is associated with clinical outcome and improved survival. The potential predictive value of TILs has also been investigated in regard to cytotoxic and antihuman epidermal growth factor receptor 2 (HER-2) therapies, but could also serve as a selection marker for novel immunotherapies. In this article, we review the current literature on TILs in breast cancer and discuss how TILs are emerging as a promising biomarker in mediating antitumor immunity.