Characterization of Desmoglein Expression in the Normal Prostatic Gland. Desmoglein 2 Is an Independent Prognostic Factor for Aggressive Prostate Cancer

PURPOSE The expression of desmogleins (DSGs), which are known to be crucial for establishing and maintaining the cell-cell adhesion required for tissue integrity, has been well characterized in the epidermis and hair follicle; however, their expression in other epithelial tissues such as prostate is poorly understood. Although downregulation of classical cadherins, such as E-cadherin, has been described in prostate cancer tissue samples, the expression of desmogleins has only been previously reported in prostate cancer cell lines. In this study we characterized desmoglein expression in normal prostate tissues, and further investigated whether Desmoglein 2 (DSG2) expression specifically can serve as a potential clinical prognostic factor for patients diagnosed with primary prostate cancer. EXPERIMENTAL DESIGN We utilized immunofluorescence to examine DSG2 expression in normal prostate (n = 50) and in a clinically well-characterized cohort of prostate cancer patients (n = 414). Correlation of DSG2 expression with clinico-pathological characteristics and biochemical recurrence was analyzed to assess its clinical significance. RESULTS These studies revealed that DSG2 and DSG4 were specifically expressed in prostatic luminal cells, whereas basal cells lack their expression. In contrast, DSG1 and DSG3 were not expressed in normal prostate epithelium. Further analyses of DSG2 expression in prostate cancer revealed that reduced levels of this biomarker were a significant independent marker of poor clinical outcome. CONCLUSION Here we report for the first time that a low DSG2 expression phenotype is a useful prognostic biomarker of tumor aggressiveness and may serve as an aid in identifying patients with clinically significant prostate cancer.