title: Association of MHC class I expression and lymph node metastasis of gastric carcinoma.
abstract: OBJECTIVE
  HLA gene encodes MHC, which could represent a common mechanism for enhanced antitumor immune response through T-cell cytotoxicity. Loss of HLA class I expression has been considered to be an important prognostic factor in many malignancies. We investigated the impact of HLA class I expression on lymph node metastasis in gastric carcinoma.
  
  
  METHODS
  We examined HLA class I expression in clinical samples from 349 patients by immunohistochemistry and compared primary lesions and metastatic lymph nodes. We analyzed the expression of HLA class I antigen in gastric cancer cell lines using flow-cytometry and HLA-A typed these cell lines using PCR.
  
  
  RESULTS
  HLA class I expression was down-regulated in metastatic lymph nodes compared with its expression in primary lesion. Patients with negative expression showed a significantly poorer prognosis. We observed down-regulation of HLA class I antigen in OCUM-2MLN cell line, which has a high potential for metastasizing to lymph node. PCR-SBT analysis indicated LOH of HLA-A gene in OCUM-2MLN.
  
  
  CONCLUSIONS
  We showed that HLA class I expression was abrogated in tumor cells that had metastasized to lymph nodes. We further suggest that loss of HLA class I due to LOH was associated with lymph node metastasis.
authors.affiliation: Department of Surgical Oncology, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Yoshii
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Masaichi
authors.initials: M
authors.lastname: Ohira
authors.forename: Kazuya
authors.initials: K
authors.lastname: Muguruma
authors.forename: Katsunobu
authors.initials: K
authors.lastname: Sakurai
authors.forename: Naoshi
authors.initials: N
authors.lastname: Kubo
authors.forename: Masakazu
authors.initials: M
authors.lastname: Yashiro
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Sawada
authors.forename: Kosei
authors.initials: K
authors.lastname: Hirakawa
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000235:genetics / Q000276:immunology* / Q000401:mortality / Q000556:secondary*; D045744:Cell Line, Tumor; D016009:Chi-Square Distribution; D015536:Down-Regulation; D005260:Female; D005434:Flow Cytometry; D015234:HLA-A Antigens / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D019656:Loss of Heterozygosity; D008198:Lymph Nodes / Q000276:immunology* / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016133:Polymerase Chain Reaction; D011379:Prognosis; D016016:Proportional Hazards Models; D013274:Stomach Neoplasms / Q000235:genetics / Q000276:immunology* / Q000401:mortality / Q000473:pathology*; D013997:Time Factors
chemical_list: D015234:HLA-A Antigens