GDNF and central nervous system cancer: The fractions were lyophilized and then screened for modulation of neurotrophic (BDNF: brain-derived neurotrophic factor; and GDNF: glial cell-derived neurotrophic factor) and neuroprotective (HSP70: heat shock protein 70) signaling in C6 glioma cells at an initial concentration of 50 μg/mL.