Hallmarks of CT26 immunogenicity are a high infiltration by leucocytes and effector immune subpopulations, a functional and highly expressed MHC class I system, high expression of both immune-activation and immune-suppression genes, high cytolytic activity (CYT) quantified as granzyme A and perforin expression, reduced in vivo tumor growth yet normal in vitro replication rate, and partial sensitivity to anti-CTLA-4 therapy [27,31,36]. The gene discussed is CTLA4; the disease is neoplasm.