Potential effector cells responsible for tumor killing include MHC-nonrestricted cells such as NK cells [28-30], lymphokine-activated killer (LAK) cells [28,31], BCG-activated killer cells [32-34], CD-1-restricted CD8+ T cells,[35] γδ T cells [36-38], NKT cells [37-39], neutrophils [40,41], macrophages [42-44], and MHC-restricted CD8+ and CD4+ T cells [45-48]. This evidence concerns the gene CD8A and neoplasm.