Tumour-infiltrating lymphocytes and the emerging role of immunotherapy in breast cancer

Abstract

Breast cancer has not previously been considered a highly immunogenic cancer. Observations of tumour-infiltrating lymphocytes (TILs) in and around neoplastic cells in tumour samples, and associations with improved pathological complete response and clinical survival end points have changed our perspective on this. Lymphocytic infiltrates have long been observed in breast cancer; however, more recently, retrospective analysis of prospectively collected tissue samples from clinical trials has demonstrated the potential role of host immunosurveillance in influencing the biology of breast cancer. This association appears to be strongest in triple negative and HER2 positive breast cancer subtypes..