Clinical Significance of Sphingosine 1-phosphate Receptor 2 and Takeda G Protein-coupled Receptor 5 in Extrahepatic Cholangiocarcinoma Patients.

Abstract

In biliary epithelial cells, two bile acid receptors, sphingosine 1-phosphate receptor 2 (S1PR2) and Takeda G protein-coupled receptor 5 (TGR5) have been reported to trigger cell proliferation, as well as neoplastic cell invasiveness. In this study, we aimed to investigate the clinical significance of S1PR2/ TGR5 expression in extrahepatic cholangiocarcinoma (CCA) patients. Patients who underwent surgical resection of extrahepatic CCA at Korea University Guro Hospital between 2002 and 2018 were included. Data on immunohistochemical staining and H-score of S1PR2 and TGR5 were evaluated using digital image analysis. A total of 115 cases of invasive CCA were analyzed. The H-score of S1PR2 showed a decrease in invasive CCA (p=0.052) but that of TGR5 showed a significant increase (p=0.02). Overall survival and disease-free survival were significantly lower in the low S1PR2 expression group (p<0.05) than in the control group; however, TGR5 expression was not significant (p=0.096). In multivariate analysis, low S1PR2 was only significant for poor prognosis. Low S1PR2 level was the only independent poor prognostic factor in patients with resected extrahepatic CCA.