title: The expression of five different claudins in invasive breast carcinomas: comparison of pT1pN1 and pT1pN0 tumors.
abstract: The evaluation of the role of claudins (CLDNs) in breast carcinogenesis has recently begun. We investigated the expression of CLDNs 1, 2, 3, 4, and 7 in pT1pN0 and pT1pN1 invasive ductal breast carcinomas. Tissue arrays of 30-30 pT1pN0 and pT1pN1 invasive ductal breast carcinomas of different grades were constructed, and the expression of CLDN 1, 2, 3, 4, and 7 proteins was analyzed using standard and immunofluorescent immunohistochemistry. The results were evaluated by light and confocal microscopy. Regarding CLDN 1, 4, and 7 expressions, differences were noted between normal and tumor cells and also between tumors of different grades, while no remarkable differences were noted between pT1pN0 and pT1pN1 tumors. CLDNs 1 and 7 were found to be downregulated in tumor cells compared to the normal epithelium, while CLDN 4 expression was decreased in grade 1 tumors. CLDN 7 protein was abundant in normal epithelia, and the staining decreased in grade 3 tumors. There were no differences between normal and neoplastic cells regarding CLDN 2 and 3 expressions. As a preliminary result, our observations suggest that the analyzed CLDNs do not promote tumor metastasis. On the basis of our findings, it seems that CLDN 1, CLDN 4, and CLDN 7 may rather have an important role in tumorigenesis or in cell-to-cell adhesion.
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest, Ulloi út, Hungary.
authors.forename: Anna-Mária
authors.initials: AM
authors.lastname: Tokés
authors.forename: Janina
authors.initials: J
authors.lastname: Kulka
authors.forename: Sándor
authors.initials: S
authors.lastname: Paku
authors.forename: Miklós
authors.initials: M
authors.lastname: Máthé
authors.forename: Csilla
authors.initials: C
authors.lastname: Páska
authors.forename: Csaba
authors.initials: C
authors.lastname: Lódi
authors.forename: András
authors.initials: A
authors.lastname: Kiss
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Schaff
mesh_terms: D001365:Axilla; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000556:secondary; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008565:Membrane Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D009363:Neoplasm Proteins / Q000378:metabolism*; D009367:Neoplasm Staging; D040081:Protein Array Analysis; D046888:Tissue Array Analysis
chemical_list: D008565:Membrane Proteins; D009363:Neoplasm Proteins