Characterized by its rapid outgrowth as both primary tumors and metastatic lesions, the B16-F1 subline has also been shown to elicit dysfunctional CD8+ T cell responses (9) that mimic those frequently observed in many melanoma patients (10–12), and soluble factors derived from this tumor have been shown to alter the function of dendritic cells (DC) as well (13–15). The gene discussed is CD8A; the disease is neoplasm.