Cytokine network in immunosuppression and tumor development in glioblastoma.

Glioblastoma (GBM) remains one of the most aggressive primary brain tumors, with a profoundly immunosuppressive microenvironment. Cytokines, chemokines, and growth factors are central to this immunosuppression, impairing the function of T cells, NK cells, dendritic cells, and promoting the recruitment of regulatory immune populations. Importantly, these soluble mediators also act directly on glioma cells, enhancing their proliferation, survival, invasion, and resistance to therapy. This chapter outlines the intricate network of cytokine-driven pathways in GBM, emphasizing their immunosuppressive functions and tumor-intrinsic effects, and discusses their implications for therapeutic intervention. Key factors such as TGF-β and IL-10 are highlighted for their dual roles in modulating immune responses and promoting tumor growth, while other cytokines, including IL-6, IL-1β, and CXCL12, contribute to a highly dynamic and redundant signaling environment. Type I and II interferons, traditionally seen as antitumoral, are shown to have paradoxical effects under chronic exposure, promoting immune exhaustion and inhibitory immune checkpoint upregulation. Given the complexity and adaptability of cytokine networks in GBM, single-target strategies have had limited success. Future therapies will need to adopt a systems-level approach, simultaneously disrupting multiple pathways and considering the spatial and temporal heterogeneity of the tumor microenvironment to achieve durable clinical responses.