CNR1 and colon carcinoma: Indeed, if on one hand an increase, although with a different pattern and extent, of endocannabinoid receptors CB1 and CB2 in various types of cancers has been observed, on the other hand the endocannabinoid system seems to play a tumor suppressing role on colon carcinoma in a genetic modified mouse model, carrying a knockdown of CB1 gene [93].