title: RCAS1 expression as a prognostic factor after curative surgery for extrahepatic bile duct carcinoma.
abstract: 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.
authors: Department of Surgical Oncology, Division of Cancer Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan. suzuoki@med.hokudai.ac.jp
authors: Masato
authors: M
authors: Suzuoki
authors: Yasuhiro
authors: Y
authors: Hida
authors: Masaki
authors: M
authors: Miyamoto
authors: Taro
authors: T
authors: Oshikiri
authors: Kei
authors: K
authors: Hiraoka
authors: Yoshihiro
authors: Y
authors: Nakakubo
authors: Toshiya
authors: T
authors: Shinohara
authors: Tomoo
authors: T
authors: Itoh
authors: Shunichi
authors: S
authors: Okushiba
authors: Satoshi
authors: S
authors: Kondo
authors: Hiroyuki
authors: H
authors: Katoh
mesh_terms: 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
chemical_list: D000951:Antigens, Neoplasm; D000954:Antigens, Surface; C120762:EBAG9 protein, human