Endocannabinoid system expression in ovarian epithelial tumors according to the dualistic model of ovarian carcinogenesis

OBJECTIVE: Our study aimed to confirm the expression of the endocannabinoid system in the human epithelial ovarian tumors, assessing the immunohistochemical expression of Cannabinoid Receptor Type 1 and Fatty Acid Amide Hydrolase in benign, borderline and malignant tumors. MATERIALS AND METHODS: Cannabinoid Receptor Type 1 and Fatty Acid Amide Hydrolase immunohistochemical expression was determined in 118 epithelial ovarian tumors sequentially treated during the last decade in our department: 36 benign, 34 borderline and 48 malignant neoplasms. Cannabinoid Receptor type 1 and Fatty Acid Amide Hydrolase expression resulted predominantly weak-moderate in the benign and borderline forms. RESULTS: concerning malignant tumors, Cannabinoid Receptor Type 1 expression resulted predominantly moderate-strong in Type I tumors and negative-weak in Type II tumors. Fatty Acid Amide Hydrolase expression resulted, instead, independent by the tumor types. Furthermore, there was no significant difference in the Cannabinoid Receptor Type 1 and Fatty Acid Amide Hydrolase expression relatively to the tumoral stages. CONCLUSIONS: The present study confirmed a variable expression of the endocannabinoid system in human ovarian tumors. Cannabinoid Receptor Type 1 expression was significantly different in malignant epithelial ovarian tumors according to dualistic model of ovarian carcinogenesis. Thus, in the most aggressive types II ovarian tumors, Cannabinoid Receptor Type 1 expression resulted predominantly negative or weak.