FASLG and glioblastoma: In the presence of the Fas ligand, IL-22 significantly decreases the apoptotic ratio of U87MG (Fig. 2C) and U118MG cell lines (Fig. 2D), whereas no significant effect was observed on cells cultured in medium alone (Fig. 2C and 2D), suggesting that IL-22 protects GBM cells from Fas ligand-induced apoptosis.