MC1R and neoplasm: Of note, in mice injected with α-MSH stimulated CD8+ T cells from C57BL/6Je/e mice we did neither observe a reduction in tumor growth nor an increased infiltration of granzyme B expressing CD8+ T cells into the tumors (data not shown) again demonstrating that α-MSH/MC-1R signaling is required for the induction of cytotoxic gene expression and cytolytic activity in CD8+ T cells.