Testing the role of known activity-regulated glioma mitogens NLGN3 and BDNF, we found that neither sequestering NLGN3 with neurexin-1(NRXN1) (3) nor inhibiting the BDNF receptor TrkB with ANA-12 fully reverted the effects of serotonergic neuronal activity-regulated secreted factors on glioma proliferation to baseline levels (fig. Here, NRXN1 is linked to glioma.