A total of eight up-regulated genes, namely TREM1, IBSP, SAA1, IL-8, MMP9, PLA2G2A, POSTN, and CHI3L1, were found in the glioma tissues with elevated M2 macrophages, employing a threshold of |LogFC| ≥ 1 and an adjusted p value < 0.05 (Figs. 1E and 1F). Here, MMP9 is linked to central nervous system cancer.