It has been shown that nanomolar concentrations of melatonin induced the transcription of glial cell line-derived neurotrophic factor (GDNF) mRNA in C6 glioma cells (42), and that micromolar concentrations of melatonin protected C6 glioma cells from amyloid-β-induced apoptosis (43). This evidence concerns the gene GDNF and central nervous system cancer.