In fact, a chemotherapy drug previously used to treat brain tumor called etoposide, a topoisomerase II inhibitor, actually mediates glial apoptosis in the C6 glioma cell line via the ceramide pathway by inducing the release of cytochrome c, and leading to the activation of caspase-9 and caspase-3 [39]. This evidence concerns the gene CASP9 and central nervous system cancer.