The Vigorous Immune Microenvironment of Microsatellite Instable Colon Cancer Is Balanced by Multiple Counter-Inhibitory Checkpoints

We examined the immune microenvironment of primary colorectal cancer using immunohistochemistry, laser capture microdissection/qRT-PCR, flow cytometry, and functional analysis of tumor-infiltrating lymphocytes. A subset of colorectal cancer displayed high infiltration with activated CD8+ cytotoxic T lymphocyte (CTL) as well as activated Th1 cells characterized by IFNγ production and the Th1 transcription factor TBET. Parallel analysis of tumor...