Using various tumor models expressing an ovalbumin-tagged version of HER-2/neu receiving adoptive transfer with WT or cblb-deficient CD8+ T cells from OT-I T-cell receptor transgenic donor mice, the authors could demonstrate that at least some tumors (e.g., NOP18) could not be rejected due to insufficient infiltration of Ova-specific T cells into the tumor microenvironment. The gene discussed is CD8A; the disease is neoplasm.