IL6 and central nervous system cancer: The expression levels of proinflammatory cytokines such as TNF-α and interleukin (IL)-6 in the inflamed brain (Fig. 4b, c) and the blood (Supplementary Fig. 10a and b) of postsurgical U87 glioma-bearing mice were measured using commercial enzyme-linked immunosorbent assay (ELISA) kits.