TNFSF9 and central nervous system cancer: It has been reported that hypoxia-mediated lactate accumulation was taken up by macrophages, which subsequently induces M2 macrophage polarization by regulating TNFSF9 expression and promoted the secretion of cytokines such as IL-10, TGF-β, and VEGF, thereby facilitating malignant progression of glioma (29, 30).