The lack of pericytes promotes endothelial hyperplasia and abnormal vascular morphogenesis, which contributes to increased transendothelial permeability [9, 22], Pericytes can also regulate the expression of cytokines, chemokines and proteases in the tumor cell niche, which may promote immunosuppression, tumor angiogenesis, growth and metastasis [23, 24]. Therefore, pericytes might provide a critical element for the local control of both vascular-tumor cell interaction and the modulation of the anti-tumor immune response. In this work, we show that glioblastoma cells induce immunotolerant properties in brain pericytes. This may explain, at least in part, why GBM cells are not detected by the immune system during perivascular inflitration and tumor growth. Thus interference with the immunossuppressive function of pericytes may represent a novel target for the development of new therapies against GBM.