Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Pancreatology 2006;6:268–272 DOI: 10.1159/000092687 Significance of Serum Receptor-Binding Cancer Antigen (RCAS1) in Pancreatic Cancer and Benign Pancreatobiliary Diseases Hasan Özkan a Tarık Akar b Seyfettin Köklü c S ¸ ahin Çoban a Departments of a Gastroenterology and b Internal Medicine, Ankara University School of Medicine, Ankara, and c Department of Gastroenterology, Kastamonu State Hospital, Kastamonu, Turkey valuable serum marker for the diagnosis of pancreatic cancer. The RCAS1 and CA19-9 levels increase the diag- nostic efficiency of each other in pancreatic cancer. Copyright © 2006 S. Karger AG, Basel and IAP Introduction Receptor-binding cancer antigen (RCAS1) is a tumor marker that has been recognized in the last decade. It was first described in human uterine and ovarian carcinomas [1], and then the antigen has been demonstrated in vari- ous other kinds of cancer [2–12]. The majority of obser- vations include immunohistochemical studies. Several trials have been performed to determine the utility of RCAS1 as a serum marker in a few types of cancers [12– 14]. RCAS1 is thought to play a protective role for tumor cells against the immune system by inhibition of clonal expansion and induction of cell death in immunocytes [6, 15]. Therefore, there seems to be a correlation between RCAS1 expression and tumor prognosis [3, 16, 17]. RCAS1 expression was detected in various digestive system tumors, such as esophagus, stomach, colon and gallbladder cancers, hepatocellular carcinomas, and chol- angiocarcinomas [6, 7, 9, 12, 17, 18]. Up to now, although RCAS1 expression in pancreatic cancer has been report- ed in several studies [13, 16] , the serum levels of this an- Key Words Pancreatic cancer  RCAS1 antigen  CA19-9 pancreas tumor marker Abstract Background/Aims: RCAS1 is a novel tumor marker, and there are no sufficient data about the utility of this anti- gen as a serum tumor marker and about its tumor spec- ificity. We aimed at measuring the serum levels of RCAS1 in patients with pancreatic cancer and at determining its diagnostic efficacy. Methods: Sera collected from pa- tients with pancreas adenocarcinomas (39 cases) and be- nign 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 be- tween serum RCAS1 and tumor stage was also evalu- ated. Results: The serum RCAS1 levels exceeded the nor- mal limit in 92.3, 26.3, and 23.0% of the patients with pancreatic cancer and benign biliary and pancreatic dis- eases and healthy volunteers, respectively. RCAS1 had a specificity similar to that of CA19-9 in pancreatic can- cer, whereas RCAS1 had a higher sensitivity (p ! 0.05). Both tumor markers had similar predictive values of pos- itive 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 Received: April 26, 2005 Accepted after revision: October 3, 2005 Published online: April 19, 2006 Seyfettin Köklü Karargahtepe mahallesi Kumrulu sokak, 18/1 TR–06300 I ˙ ncirli, Keçiören, Ankara (Turkey) Tel. +90 312 361 2568, Fax +90 312 312 4120, E-Mail gskoklu@yahoo.com © 2006 S. Karger AG, Basel and IAP 1424–3903/06/0064–0268$23.50/0 Accessible online at: www.karger.com/pan