beta-catenin expression and claudin expression pattern as prognostic factors of prostatic cancer progression

To investigate the patterns of expression of the junctional proteins beta-catenin and claudins in different prognostic groups of patients with prostatic cancer, to determine their value as prognostic markers.

We evaluated the samples of 30 patients who had a radical prostatectomy for organ-confined cancer (pT2N0M0), men with clinically advanced cancer, and a control group with benign prostatic hyperplasia. Using immunohistochemistry applied to tissue microarrays, each group was evaluated for claudin-1, -2, -3, -4, -5, -7, -8 and -10, and beta-catenin expression.

There were differences among the three groups in the expression of claudin-1 (P = 0.001), -2 (P = 0.014), -3 (P = 0.027), -4 (P = 0.001), -8 (P = 0.001) and beta-catenin (P = 0.002), regardless of Gleason score. By contrast, claudin-5, -7 and -10 patterns were not significantly different among the groups. Furthermore, claudin-1 (P = 0.014) and -4 (P = 0.004) could be used to distinguish between those patients who had metastases and those who did not.

The pattern of claudin expression could be a novel diagnostic marker in re-classifying adenocarcinomas, and an additional sensitive predictive factor for a clinically poor prognosis. Our results suggest that patients with organ-confined and advanced cancer are subsets with distinct claudin expression profiles, and that claudin-4 is related to cellular differentiation in prostate cancer, which is not only the receptor molecule for the Clostridium perfringens enterotoxin, and thus a theoretical future therapeutic target for prostate cancer, but also a marker of progression.