The Role of Surgical Pathology in Guiding Cancer Immunotherapy

The recognition that the immune system can identify and destroy tumor cells has driven a paradigm shift in our understanding of human cancer. Therapies designed to enhance this capacity, including cancer vaccines and coinhibitory receptor blockade, have demonstrated clinical efficacy in treating tumors refractory to conventional therapy. In this review, we discuss how the analysis of the immune microenvironment in primary tissue biopsy samples can be used to stratify patients according to clinical outcome, identify patients likely to benefit from specific immunotherapies, and tailor combination immunotherapy to individual patients and tumor types. As immunotherapy gains in complexity and is used in combination with agents that target oncogenic, intracellular signaling pathways, diagnostic pathologists will play an increasingly important part in identifying and quantifying cellular and molecular biomarkers in tissue samples that reflect the nature and magnitude of the antitumor immune response.