Clinical significance of serum RCAS1 levels detected by monoclonal antibody 22-1-1 in patients with cholangiocellular carcinoma.
OBJECTIVE
The tumor-associated antigen, RCAS1, has been reported to be expressed in various types of cancer, including cholangiocarcinoma. We measured serum RCAS1 levels in patients with intrahepatic cholangiocellular carcinoma (CCC) and other hepatobiliary diseases, and examined the clinical significance of serum RCAS1 as a tumor marker.


METHODS
Sera collected from the patients and healthy volunteers were used for ELISA for RCAS1. The values of RCAS1 for CCC patients were compared to those of other tumor marker proteins.


RESULTS
Serum RCAS1 levels exceeded the normal limit in a high percentage (73.9%) of CCC patients. The positivity rate was higher than those of CA19-9 and CEA. No correlation was found between the RCAS1 and CA19-9 concentrations. Serum RCAS1 was positive in many cases that were negative for CA19-9. Surgical resection of CCC reduced the RCAS1 level to within the normal range. On the other hand, serum RCAS1 levels were elevated in very few cases of benign hepatobiliary disease.


CONCLUSIONS
As a tumor marker in CCC, RCAS1 is, at least, of complementary value to CA19-9 and CEA. Measuring serum RCAS1 contributes to the diagnostic accuracy, and is useful for estimating tumor progression or therapeutic effect.
Watanabe
Hironobu
H
Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Enjoji
Munechika
M
Nakashima
Manabu
M
Noguchi
Ken-ichi
K
Kinukawa
Naoko
N
Sugimoto
Rie
R
Kotoh
Kazuhiro
K
Nakamuta
Makoto
M
Nawata
Hajime
H
Watanabe
Takeshi
T
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000097:blood*; D001650:Bile Duct Neoplasms / Q000097:blood / Q000276:immunology* / Q000601:surgery; D001653:Bile Ducts, Intrahepatic / Q000601:surgery; D018395:CA-19-9 Antigen / Q000097:blood; D002272:Carcinoembryonic Antigen / Q000097:blood; D018281:Cholangiocarcinoma / Q000097:blood / Q000276:immunology* / Q000601:surgery; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D018395:CA-19-9 Antigen; D002272:Carcinoembryonic Antigen; C120762:EBAG9 protein, human