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Canadian Journal of Gastroenterology
Volume 20 (2006), Issue 9, Pages 593-596
Original Article

The Utility of Serum Receptor-Binding Cancer Antigen Expressed on Siso Cells in Gastrointestinal Tract Cancers

Şahin Çoban,1 Hasan Özkan,1 Seyfettin Köklü,2 Osman Yüksel,3 Muhammed Cem Koçkar,4 Tarik Akar,1 and Necati Örmeci1

1Department of Gastroenterology, Ankara University Medical School, Turkey
2Department of Gastroenterology, Ankara Education and Research Hospital, Turkey
3Department of Gastroenterology, Ankara Numune Hospital, Ankara, Turkey
4Department of Gastroenterology, Suleyman Demirel University Medical School, Isparta, Turkey

Received 12 January 2006; Accepted 30 January 2006

Copyright © 2006 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


BACKGROUND: Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is a novel tumour marker that has been described in various kinds of cancer. The majority of observations include immunohistochemical studies; however, there are not enough data about the utility of this antigen as a serum tumour marker and its tumour specificity.

AIM: To measure the serum levels of RCAS1 in patients with gastrointestinal (GI) tract cancers and compare them with other GI tract tumour markers.

PATIENTS AND METHODS: Sera collected from patients with GI cancers (14 esophagus, 32 gastric and 36 colon) and from healthy volunteers (30 individuals) were analyzed for RCAS1 and compared with carcinoembryonic antigen (CEA) and cancer antigen 19-9. The relationship between serum RCAS1, tumour stage and tumour grade was also evaluated.

RESULTS: Mean serum RCAS1 level was higher in patients with GI tract cancers compared with the control group (P=0.001). Among GI tract cancers, RCAS1 had lowest and highest sensitivity for esophagus and colon cancer diagnosis, respectively. Serum RCAS1 had a higher sensitivity for malignancy, except in the colon, and lower specificity in all groups compared with CEA. In comparison with cancer antigen 19-9, serum RCAS1 was more sensitive but less specific for all GI cancer groups. Mean serum RCAS1 levels were not statistically significant among histopathological tumour types (P>0.05). Although serum RCAS1 levels were significantly higher in cases with lymph node involvement compared with lymph node-negative cases (P=0.009), there was no difference between cases with and without serosal involvement, vascular invasion and distant metastasis; no correlation was found between tumour size and RCAS1 levels.

CONCLUSIONS: RCAS1 may be used and combined with CEA as a tumour marker in GI tract cancers.