ITGA4 and brain neoplasm: The immune cells identified in brain tumors are mainly macrophages (BMDMs, CD45high, CD49D/ITGA4+), tissue-resident microglia (CD45low, CD49D/ITGA4-, (Lisi et al., 2017; Quail and Joyce, 2017), T cells, B cells, NK cells (Masson et al., 2007; Geller and Miller, 2011), Myeloid-Derived Suppressor Cells (MDSCs (Abad et al., 2014); and Dendritic Cells (DCs; (Quail and Joyce, 2017).