Cannabinoid receptor expression in estrogen-dependent and estrogen-independent endometrial cancer

Abstract

The lack of good diagnostic/prognostic biomarkers and the often late presentation of endometrial cancer (EC) hinders the amelioration of the morbidity and mortality rates associated with this primarily estrogen-driven disease, a disease that is becoming more prevalent in the population. Previous studies on the expression of the classical cannabinoid receptors, CB1 and CB2, suggest these could provide good diagnostic/prognostic biomarkers for EC but those observations have been contradictory. In this study, we sought to resolve the inconsistency of CB1 and CB2 expression levels in different EC studies. To that end, we used qRT-PCR and immunohistochemistry (IHC) for CB1 and CB2 in endometrial biopsies from women with or without EC and found that transcript levels for both CB1 and CB2 were significantly decreased by 90 and 80%, respectively in EC. These observations were supported by histomorphometric studies where CB1 and CB2 staining intensity was decreased in all types of EC. These data suggest that the loss of both types of CB receptors is potentially involved in the development of or progression of EC and that CB1 and CB2 receptor expression could serve as useful histological markers and therapeutic targets in the treatment of or prevention of EC.

Keywords:

• Cannabinoid receptor
• endometrial cancer
• endometrioid
• non-endometrioid
• estrogen

Acknowledgements

We thank Dr Howard Pringle (Department of Cancer Studies and Molecular Medicine) for allowing us to use his StepOne Plus RT-PCR machine and Linda Jane Potter for teaching TA how to use it. The authors thank Mr Quentin Davies and Miss Esther Moss for providing the uterine samples and Dr Lawrence Brown’s help in providing the cut tissues samples and the classification of the EC grades as per FIGO classification.

Disclosure statement

The authors declare no conflicts of interest related to this work.

Additional information

Funding

This work was funded by grants from the University Hospitals of Leicester NHS Trust.