title: Loss of heterozygosity in the HLA class I region in human pancreatic cancer.
abstract: An altered human leukocyte antigen (HLA) class I expression constitutes an important tumor-escape mechanism counteracting T-cell mediated immune responses. We utilized the technique of microsatellite analysis to characterize the loss of heterozygosity (LOH) in the HLA class I region in 24 samples of patients with human ductal pancreatic carcinoma. The expression of HLA class I and the infiltration by T cells were studied in parallel by standard immunohistochemistry. The present study demonstrates LOH in the HLA class I region in five patients with pancreatic carcinoma. Immunohistochemical analysis showed that pancreatic carcinomas were frequently characterized by a total or partial loss of expression in HLA class I antigen. The positive or negative LOH status corresponded with the expression analysis in eight cases. Reduction of HLA class I expression without LOH was found in 14 cases. Lymphocyte infiltration with CD3+, CD4+, and CD8+ T cells did not show significant differences between LOH-positive and LOH-negative tumors. In conclusion, LOH does not seem to be the only factor for the reduced expression of HLA class I antigen as well as for the T-cell infiltration in this type of tumor.
authors.affiliation: Department of Surgery, University of Heidelberg, Heidelberg, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Ryschich
authors.forename: O
authors.initials: O
authors.lastname: Cebotari
authors.forename: O V
authors.initials: OV
authors.lastname: Fabian
authors.forename: F
authors.initials: F
authors.lastname: Autschbach
authors.forename: J
authors.initials: J
authors.lastname: Kleeff
authors.forename: H
authors.initials: H
authors.lastname: Friess
authors.forename: A
authors.initials: A
authors.lastname: Bierhaus
authors.forename: M W
authors.initials: MW
authors.lastname: Büchler
authors.forename: J
authors.initials: J
authors.lastname: Schmidt
mesh_terms: D017252:CD3 Complex / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology; D016827:CD8 Antigens / Q000276:immunology; D021441:Carcinoma, Pancreatic Ductal / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D002896:Chromosomes, Human, Pair 6 / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques; D019656:Loss of Heterozygosity; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D018895:Microsatellite Repeats; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I