NOS2 and central nervous system cancer: Since the expression of inflammatory-related mediators, such as COX-2 and iNOS, was found to be downregulated in the brain tissue of the IOE mouse group when compared with that of the LPS mouse group (Figure 3C), we checked again the effects of IOE on the LPS-induced expression of COX-2 and iNOS on C6 glioma cells.