title: The expression of RCAS1 and tumor infiltrating lymphocytes in patients with T3 gastric carcinoma.
abstract: BACKGROUND
  This study aimed to assess the prognostic value of receptor binding cancer antigen expressed on SiSo cells (RCAS1) expression and host immune response in gastric carcinomas.
  
  
  METHODS
  We investigated the relationship between RCAS1 expression, density of tumor-infiltrating lymphocytes (TIL), and clinicopathological findings in 129 patients with T3 gastric carcinoma who underwent curative surgery.
  
  
  RESULTS
  RCAS1 immunoreactivity was detected in the membrane and cytoplasm of tumor cells. Positive immunoreactivity for RCAS1 was detected in 70 patients (54.3%) and high expression levels of RCAS1 were found in 33 patients (25.6%). The expression of RCAS1 significantly correlated with the histological type of carcinoma and lymph node metastasis. Apoptotic rates in TILs showed marginally higher significance in patients with high RCAS1 expression than in those with low expression. The 5-year survival rates were 77.9% in patients with low RCAS1 expression and 48.4% in those with high RCAS1 expression. Although there was no significant difference in survival between the patients with marked and slight infiltration of TILs, frequent apoptosis in TILs indicated significantly worse prognosis. Patients with low RCAS1 expression survived significantly longer than those with high RCAS1 expression, as did those patients with a high rate of apoptosis in TILs. Multivariate analysis revealed that RCAS1 expression, as well as tumor size and lymph node metastasis, was an independent prognostic factor.
  
  
  CONCLUSIONS
  The expression of RCAS1 was significantly correlated with poor prognosis in patients with T3 gastric carcinoma. RCAS1 protein may play an important role in the evasion of tumor cells from immunological defense mechanisms in human gastric carcinoma.
authors.affiliation: First Department of Surgery, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago 683-8504, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Fukuda
authors.forename: Shunichi
authors.initials: S
authors.lastname: Tsujitani
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Maeta
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Masahide
authors.initials: M
authors.lastname: Ikeguchi
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Kaibara
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000378:metabolism*; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016246:Lymphocytes, Tumor-Infiltrating / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D015996:Survival Rate
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; C120762:EBAG9 protein, human