CNR1 and central nervous system cancer: While most studies have demonstrated that CBD has low affinity for CB1R and CB2R, research by McKallip et al. and Massi et al. revealed that in lymphoma and acute lymphoblastic leukaemia (ALL) cell lines and human glioma cell lines, respectively, CBD (2.5 μM/0.8 mg/L) induced apoptosis through a CB2R-specific mechanism, and not via binding to either CB1R or TRPV1 [51,97] (Figure 2).