Immunohistochemical profiles of claudin-3 in primary and metastatic prostatic adenocarcinoma

Tissue microarrays were immunohistochemically stained for claudin-3, with the staining intensities subsequently quantified and statistically analyzed using a one-way ANOVA with subsequent Tukey tests for multiple comparisons or a nonparametric equivalent. Fifty-three cases of NAC, 17 cases of BPH, 35 cases of PIN, 107 cases of PCa, and 55 cases of Mets were analyzed in the microarrays.PCa and Mets had the highest absolute staining for claudin-3. Both had significantly higher staining than BPH (p < 0.05 in both cases) and NAC (p < 0.05 in both cases). PIN had a lower, but non-significant, staining score than PCa and Mets, but a statistically higher score than both BPH and NAC (p < 0.05 for both cases). No significant differences were observed between PCa, Mets, and PIN.To our knowledge, this represents one of the first studies comparing the immunohistochemical profiles of claudin-3 in PCa and NAC to specimens of PIN, BPH, and Mets. These findings provide further evidence that claudin-3 may serve as an important biomarker for prostate cancer, both primary and metastatic, but does not provide evidence that claudin-3 can be used to predict risk of metastasis.During 2010 alone, 32,050 deaths attributable to prostate cancer are expected to occur in the United States, making it the second leading cause of cancer death in males[1]. Despite this, studies conducted before the era of prostate specific antigen (PSA) screening have shown that latent prostate cancer was often diagnosed only after autopsy in older males[2-4]. One autopsy study of males over the age of 50, also conducted before PSA screening was implemented, indicated that the overall age-adjusted prevalence of latent prostate carcinoma was as high as 34.6% for whites and 36.9% for blacks in the United States[5], providing evidence that not all cases of prostate cancer have the same clinical aggressiveness. Based upon cases of prostate cancer diagnosed by PSA, researchers have estimated that clinically insignifican