As the percentage of CD45+ CD11b+ Ly6+ cells correlated negatively with the percentage of entries in the novel arm of the spatial Y maze, a cognitive measure not affected by conventional irradiation, and CD11+ Ly6G+ cells were shown to inhibit tumor growth [26], these data suggest that some immune measures in the hippocampus might have opposite effects on cognition versus tumor control. This evidence concerns the gene PTPRC and neoplasm.