Notably, microscopic evaluation of immunostained sections showed that in challenged GL261 brain hemispheres, CD4+ T cells were widely distributed within the tumor bed and along its margins (Figure 7B; pre-vaccinated, tum WT, insets ×400), whereas they were less abundant and dispersed throughout the GL261 tumor mass in non-vaccinated mice (Figure 7B; non-vaccinated, tum WT, insets ×400). This evidence concerns the gene CD4 and neoplasm.