The mechanisms of anti-cancer action for both ∆9-THC and non-THC cannabinoids remains enigmatic, however, most studies suggest that ∆9-THC induces apoptosis and cytotoxicity via CBR-dependent pathways [50,51,52], while non-THC cannabinoids, such as CBD, modulate the activity of other de-orphan and orphan G-protein-coupled receptors (GPCRs) and non-GPCRs. This evidence concerns the gene CBR1 and cancer.