C5 and glioblastoma: Lim et al. (2020) found that MSLCs in the glioma microenvironment express and secrete high levels of C5a, which increases the expression of ZEB1 through C5aR1 and the activation of the p38-MAPK pathway in a paracrine manner. This signaling pathway promotes the invasion and migration of GBM cells, which relates to the prognosis of GBM patients (Lim et al., 2020; Figure 2C).