title: Analysis of E-cadherin in diffuse-type gastric cancer using a mutation-specific monoclonal antibody.
abstract: In-frame deletions from the E-cadherin mRNA, coding for a homophilic cell adhesion molecule, are characteristic for diffuse-type gastric carcinomas. Using immunohistochemical analysis the mutant form cannot be distinguished from normal E-cadherin, making results difficult to interpret. In this study, a rat monoclonal antibody, designated E-cad delta 9-1, was generated against a peptide spanning the fusion junction region between exons 8 and 10. This new epitope is present in an E-cadherin variant that lacks exon 9 from the mRNA due to different splice-site gene mutations. Using Western blotting and immunohistochemistry of E-cadherin-transfected cells, we demonstrate that E-cad delta 9-1 specifically reacts with E-cadherin lacking exon 9 but not with the wild-type protein. No immunoreactivity was observed in 31 nontumorous and embryonal tissues analyzed. In gastric carcinoma specimens known to express mutant E-cadherin mRNA lacking exon 9, E-cad delta 9-1 targets exclusively tumor cells in routine formalin-fixed and paraffin-embedded material from biopsies, primary tumors, and lymph node metastases. In a retrospective series of 172 diffuse-type gastric carcinomas expressing E-cadherin, E-cad delta 9-1 reacted with 22 tumors (13%). This new tumor marker-monoclonal antibody system could open novel avenues for selective diagnosis and specific therapy of a subgroup of diffuse-type gastric cancer patients.
authors.affiliation: Technische Universität München, Klinikum rechts der Isar, Institut für Pathologie, München, Germany. kf.becker@lrz.tum.de
authors.forename: K F
authors.initials: KF
authors.lastname: Becker
authors.forename: E
authors.initials: E
authors.lastname: Kremmer
authors.forename: M
authors.initials: M
authors.lastname: Eulitz
authors.forename: I
authors.initials: I
authors.lastname: Becker
authors.forename: G
authors.initials: G
authors.lastname: Handschuh
authors.forename: C
authors.initials: C
authors.lastname: Schuhmacher
authors.forename: W
authors.initials: W
authors.lastname: Müller
authors.forename: H E
authors.initials: HE
authors.lastname: Gabbert
authors.forename: A
authors.initials: A
authors.lastname: Ochiai
authors.forename: S
authors.initials: S
authors.lastname: Hirohashi
authors.forename: H
authors.initials: H
authors.lastname: Höfler
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D015153:Blotting, Western; D015820:Cadherins / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D000939:Epitopes; D006801:Humans; D007150:Immunohistochemistry; D009154:Mutation; D012333:RNA, Messenger; D051381:Rats; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D015820:Cadherins; D000939:Epitopes; D012333:RNA, Messenger