The ability of tetrahydrocannabinol to activate human TRPV2 (hTRPV2) [14] and our finding of higher TRPV2 expression in invasive bladder tumors together with the palliative use of cannabinoids in cancer treatment [69] could encourage the use of THC as an adjuvant in the treatment of severe and persistent bladder cancer pain. This evidence concerns the gene TRPV2 and cancer.