Abstract IA16: Clinical relevance of host immunity in breast cancer

Abstract

Abstract The clinical relevance of the host immune system in breast cancer has long been unclear. Recently an appreciation of the biological heterogeneity of breast cancer has prompted investigation of the immune system's role in the different molecular breast cancer subtypes. A robust association between a more favourable prognosis and the presence of high levels of lymphocytic infiltration has been found in early-stage triple negative and HER2-positive breast cancer. These infiltrates seem to represent favorable anti-tumor immune responses, suggesting that activation of host immunity will be important for improving survival outcomes. The biological influences underlying the immune response are incompletely understood.My talk will review recent data supporting the clinical relevance of host anti-tumor immunity as represented by lymphocytic infiltration, the composition of the infiltrate in breast cancer and how this biomarker could be used in the clinical setting. Lymphocytic infiltration may be important as a biomarker in breast cancer prognosis: efforts to standardize the methodology for evaluating TILs in clinical breast cancer specimens in routine histopathological practise are ongoing. I will also discuss the rationale for enhancing immunity in breast cancer, including data on the efficacy of T-cell checkpoint inhibition..