CCL2 and central nervous system cancer: To investigate whether CYB561D2-activated STAT3 induces the expression of immunosuppressive genes in gliomas, we measured protein expression of FASLG [30], TGF-β2 [31], CD70 [32], PD-L1 [33], PD-L2 [34], CCL2 [35] and TDO2 [36] in U251 and U87 transfected with CYB561D2 plasmid for 48 h.