The endocannabinoid system is comprised of cannabinoid receptors(CB1 and CB2), their endogenous ligands (endocannabinoids), and proteins responsible for their metabolism participate in many different functions indispensable to homeostatic regulation in several tissues, exerting also antitumorigenic effects. The present study aimed to evaluate the clinical significance of CB1 and CB2 expression in human benign and malignant thyroid lesions. CB1 and CB2 proteins’ expression was assessed immunohistochemically on paraffin-embedded thyroid tissues obtained from 87 patients with benign ( = 43) and malignant ( = 44) lesions and was statistically analyzed with clinicopathological parameters, follicular cells’ proliferative capacity, and risk of recurrence rate estimated according to the...