Decreased expression of is a potential biomarker of prostate cancer progression.

Differentiation of indolent and aggressive prostate carcinoma (PCa) at the time of diagnosis is currently one of the major challenges. This study aimed at identification of prognostic biomarkers to aid in predicting biochemical recurrence (BCR) of the disease. Microarray-based gene expression profiling in tissues of 8 BCR and 8 No-BCR cases revealed expression differences of 455 genes, most of which were down-regulated in BCR cases. Eleven genes were selected for validation by real-time PCR in the first PCa cohort (N = 55), while seven of them were further validated in the second, independent, PCa cohort (N = 53). Down-regulation of (p < 0.001) and (p = 0.002) expression and up-regulated levels of (p = 0.025) were specific biomarkers of BCR in at least one of the two PCa cohorts, but only expression retained the independent prognostic value in a multivariate analysis (p < 0.001). DNA methylation analysis (114 PCa and 24 non-cancerous tissues) showed frequent methylation in PCa (p < 0.001) and was associated (p < 0.010) with the down-regulated expression in one PCa cohort. The results of our study suggest down-regulation as a potential feature of aggressive PCa.