ICOSLG and neoplasm: To evaluate whether CXCL8 and ICOSLG were expressed by other cells than tumor cells in the brain TME, we interrogated previously published RNA sequencing data from purified cerebral cell populations13 and single-cell RNA data from GBM specimens.14 In healthy human brain and GBM CXCL8 was mainly expressed in immune cells and vascular cells (Figure 2E and F).