Many pre-clinical studies and histological analysis of patient tumours, suggest that an upregulation in the CB1 and CB2 receptors, endogenous ligands and over-activation of the ECS correlates with more aggressive tumours (Dariš et al. 2019) although other reports have concluded the contrary (Jung et al. 2013; Tutino et al. 2019). The gene discussed is CNR1; the disease is neoplasm.