Cannabinoid CB1 receptor is expressed in chromophobe renal cell carcinoma and renal oncocytoma

Objective: To analyze the mRNA and protein expression of cannabinoid receptors CBI and CB2 in chromophobe renal cell carcinoma (ChRCC) and renal oncocytoma (RO). Design and methods: Fresh and formalin-fixed tissue samples of ChRCC and RO were analyzed by using real-time quantitative RT-PCR and immunohistochemical techniques (n=40). Results: Quantitative RT-PCR analysis showed that CB1 mRNA was underexpressed by 12-fold in ChRCC and had a variable expression in RO. CBI protein showed intense positive immunostaining in both neoplasms. Both CB2 mRNA and protein were not expressed in tumor and non tumor renal tissue. Conclusion: This distinct immunoprofile may eventually be used as an additional tool with practical interest in the differential diagnosis of renal tumors. (C) 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.