Immune activation of brain pericytes, which act as mediators of neuroinflammation, specifically leads to the expression of several pro-inflammatory cytokines, co-stimulatory molecules and Major Histocompatibility Complex (MHC) molecules, which may modulate T cell responses [16–19]. The role of pericytes in the regulation of T cell function is poorly understood. Some authors described the ability of pericytes pre-activated by inflammatory challenge to present antigens on MHC to T cells, modulating the responses of different T cell populations, including suppressive regulatory T cells [16, 20, 21]. However, it is not well known if brain pericytes are immunologically protective in response to tumor formation or if, by contrast, they might fail to activate antigenic T cell responses, preventing tumor clearance.