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.
ASJC Scopus subject areas
- Pathology and Forensic Medicine
- Cell Biology