Tumor-Infiltrating Lymphocytes in Breast Cancer

Discussions about tumor-infiltrating lymphocytes (TILs) have become potentially important with respect to both prognosis and prediction of response to immune-modulatory agents, such as checkpoint inhibitors. Early studies in breast cancer suggested that the presence of TILs in tumor tissue identified patients more likely to attain a pathologic complete response following neoadjuvant therapy and that risk for recurrence and death were reduced with increasing numbers of TILs in the primary breast specimens from patients with triple-negative breast cancer (TNBC) following adjuvant chemotherapy.

Because the number of patients available for analysis in these early studies was small, investigators undertook a systematic review of 15 clinical repor…