RCAS1 expression as a prognostic factor after curative surgery for extrahepatic bile duct carcinoma.
BACKGROUND
RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is a cancer cell-surface antigen and has been identified as a prognostic factor in several cancers. It is thought that tumor cells escape from immune attack by expressing RCAS1, which induces apoptosis in receptor-positive immune cells. We investigated the relationship between RCAS1 expression and clinicopathologic features and clinical outcome in patients with extrahepatic bile duct carcinoma (EBDC) who underwent curative resection.


METHODS
RCAS1 expression was determined by immunohistochemistry in 60 patients with EBDC who underwent curative resection from 1992 to 1999. The patients were divided into two groups on the basis of the extent of RCAS1 expression: a low-expression group (immunoreactivity in <25% of cells) and a high-expression group. Expression was correlated with clinicopathologic features and prognosis.


RESULTS
RCAS1 was expressed in 52 (86.7%) of 60 tumors and at a high frequency in all histopathologic stages. High expression of RCAS1 was detected in 46 (76.7%) of 60 cases. No correlation existed between the pattern of RCAS1 expression and any clinicopathologic feature, although high expression did correlate with poor prognosis. High RCAS1 expression was an independent negative predictor for survival.


CONCLUSIONS
RCAS1 expression predicts poor outcome in resectable EBDC.
Suzuoki
Masato
M
Department of Surgical Oncology, Division of Cancer Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan. suzuoki@med.hokudai.ac.jp
Hida
Yasuhiro
Y
Miyamoto
Masaki
M
Oshikiri
Taro
T
Hiraoka
Kei
K
Nakakubo
Yoshihiro
Y
Shinohara
Toshiya
T
Itoh
Tomoo
T
Okushiba
Shunichi
S
Kondo
Satoshi
S
Katoh
Hiroyuki
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm; D000954:Antigens, Surface / Q000378:metabolism*; D001650:Bile Duct Neoplasms / Q000378:metabolism* / Q000601:surgery; D017734:Bile Ducts, Extrahepatic; D002277:Carcinoma / Q000378:metabolism* / Q000601:surgery; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models
D000951:Antigens, Neoplasm; D000954:Antigens, Surface; C120762:EBAG9 protein, human