CNR1 and central nervous system cancer: Initial studies showed that cannabinoids can induce apoptosis of glioma cells via CB1R and CB2R dependent de novo synthesis of the sphingolipid ceramide which has pro-apoptotic properties (Galve-Roperh et al., 2000; Sanchez et al., 2001; Gomez del Pulgar et al., 2002; Blázquez et al., 2004).