Syndecan-1 expression in prostate cancer and its value as biomarker for disease progression

OBJECTIVE To evaluate the association between syndecan-1 (CD138) expression and prostate cancer. PATIENTS AND METHODS We evaluated syndecan-1 expression using a recently constructed tissue microarray of prostatic samples taken from 243 patients, corresponding to 1400 cores, with 69.8%, 5.6%, 17.6% and 7% of the cores representing localized prostate cancer, high-grade prostatic intraepithelial neoplasia, benign prostate tissue and hormone refractory/metastatic disease, respectively. RESULTS Metastatic cases had the highest frequency and membranous staining intensity for syndecan-1 overexpression, followed by hormone refractory and localized disease (83.3% vs 34.8% and 25.7%, respectively). There was no significant difference in the frequency of membranous syndecan-1 expression between localized prostate cancer and benign glands (25.7% vs 24.7% of cases, respectively). However, benign glands showed significantly higher intensity staining than localized prostate cancer. We found no significant association between syndecan-1 expression and any of the following: Gleason score, pathological stage, surgical margin status and biochemical recurrence. CONCLUSION The current available evidence, from the present and previous studies, show that syndecan-1 is not an independent predictor of recurrence or tumour-specific survival, diminishing its significance as a clinical marker.