PTGS2 and endometriosis: 33,42 Moreover, EP2 receptorexpression is also very high in the uterus,20 stromal cells in lesions, and mesothelial cells in the peritoneum.33 Based on this COX2/PGE2/EP2 signaling,Greaves et al. (2017)33 tested the roleof EP2 in a mouse model of endometriosis monitoring the endometriosispain mediated behaviors (licking and exploratory activities) and mechanicalwithdrawal from von Frey filament test.