Interobserver Agreement Between Pathologists Assessing Tumor-Infiltrating Lymphocytes (TILs) in Breast Cancer Using Methodology Proposed by the International TILs Working Group.

Background: The presence of tumor-infiltrating lymphocytes (TILs) in breast tumors is prognostic and predictive, suggesting that TILs may be an important biomarker. Recently, an international TILs working group formulated consensus recommendations for TIL evaluation. The current study was performed to determine interobserver agreement using that methodology.