Transgenic mice engineered to express dominant-negative TβRII in CD4+ and CD8+ T cells are resistant to tumor formation upon inoculation of syngeneic cancer cell lines, which is associated with a large expansion of tumor-reactive CD8+ T cells66, suggesting that endogenous TβRII could inhibit tumor-antigen-specific T cell priming. The gene discussed is CD8A; the disease is neoplasm.