Immunoexpression of Claudins -3, -4 and -7 in prostate adenocarcinomas

Claudins are a family of essential tight junction proteins, abnormally expressed in human carcinomas. The studies that indicated the involvement of claudins in tumor biology and progression suggest the possibility of their utility as markers for diagnosis or prognosis, but also as possible targets for therapy. We investigated 50 prostate adenocarcinomas (PAs) for which we followed the expression of Claudins -3, -4 and -7 in relation to International Society of Urological Pathology (ISUP) grades. We observed the positivity for Claudin-3, Claudin-4, and Claudin-7 in 76%, 74% and 46% of cases. Analysis of the immunoexpression pattern revealed the cytoplasmic and nuclear translocation for Claudins -3 and -4, and only cytoplasmic for Claudin-7. For all claudins investigated, we noted a final staining score with significantly higher values or at the limit of statistical significance for PA belonging to ISUP groups 1–4. The internalization of Claudins -3, -4 and -7 expression, regardless of the degree of PA, indicates their involvement in prostate carcinogenesis. In addition, the similar immunoexpression patterns of the three investigated claudins and their positive linear correlation suggest a coordinated regulation and indicate the possibility of a targeted treatment strategy.