Significance of Serum Receptor-Binding Cancer Antigen (RCAS1) in Pancreatic Cancer and Benign Pancreatobiliary Diseases

Background/Aims: RCAS1 is a novel tumor marker, and there are no sufficient data about the utility of this antigen as a serum tumor marker and about its tumor specificity. We aimed at measuring the serum levels of RCAS1 in patients with pancreatic cancer and at determining its diagnostic efficacy.Methods: Sera collected from patients with pancreas adenocarcinomas (39 cases) and benign biliary and pancreatic diseases (19 cases) and from healthy volunteers (13 cases) were analyzed for RCAS1 and the results compared with CA19-9. The relation between serum RCAS1 and tumor stage was also evaluated.Results: The serum RCAS1 levels exceeded the normal limit in 92.3, 26.3, and 23.0% of the patients with pancreatic cancer and benign biliary and pancreatic diseases and healthy volunteers, respectively. RCAS1 had a specificity similar to that of CA19-9 in pancreatic cancer, whereas RCAS1 had a higher sensitivity (p < 0.05). Both tumor markers had similar predictive values of positive and negative tests for pancreatic cancer. The RCAS1 level was less influenced than the CA19-9 level by biliary stenoses. The median serum levels of RCAS1 increased, as the tumor stage increased.Conclusions: RCAS1 is a valuable serum marker for the diagnosis of pancreatic cancer. The RCAS1 and CA19-9 levels increase the diagnostic efficiency of each other in pancreatic cancer.