CD4 and neoplasm: Glioma cells release multiple cytokines, interleukins and growth factors that promote the infiltration of various cells, including astrocytes, pericytes, endothelial cells, circulating progenitor cells, and immune cells such as microglia, peripheral macrophages, myeloid-derived suppressor cells, leukocytes, CD4 T cells, and Tregs into the tumor [62].