As shown in Figure 1E, the presence of macrophages protected glioma cells from CDDP (50 μg/ml)-induced apoptosis, an effect which was reversed in the presence of the NOS inhibitor l-NAME (2 mM, added to the cell culture 1 h before the administration of CDDP) (Figure 1E). This evidence concerns the gene NOS1 and central nervous system cancer.