VAMP2 and central nervous system cancer: Atp1b2 was selected because genes related to energy-homeostasis are very relevant in glia-neuron interactions, and Rab2a was selected because it is similarly important for vesicular fusion and trafficking as Vamp2. The mRNA for Syn2 was also analyzed as a control for a gene not expressed in glia (its mRNA was not detectable in glioma C6 cells).