Clinical Significance and Predictive Value of Prostaglandin E2 Receptors (EPR) 1-4 in Patients with Renal Cell Carcinoma

Background: The clinical significance of prostaglandin E2 receptor (EPR) expression in renal cell carcinoma (RCC) tissues remains unclear. Patients and Methods: Four subtypes of EPRs were examined in 112 human RCC tissues by immunohistochemical and Western blot analysis. The relationships between EPR immunoreactivity score (IS) and various pathological features and survival were then analyzed. Results: The IS of EP4R was significantly higher (p<0.001) in cancer cells (mean=2.7 and SD=2.1) than in normal kidney tissues (1.8 and 1.2). EP4R expression correlated with pT stage, metastasis, and grade. EP2R expression was also associated with metastasis. Expressions of both EP2R and EP4R were found to be significant predictors for cause-specific survival on Kaplan-Meier survival analysis (p=0.006 and 0.023, respectively). Conclusion: EP2R and EP4R may play important roles in malignant behavior. EP4R in particular was closely associated with pathological features, implicating this receptor as a potential therapeutic target in patients with RCC.