Expression analysis and clinical utility of L-Dopa decarboxylase (DDC) in prostate cancer

Background: L-Dopa decarboxylase (DDC) is a pyridoxal 5-phosphate-dependent enzyme that was found to be involved in many malignancies. The aim of this study was to investigate the mRNA expression levels of DDC in prostate tissues and to evaluate its clinical utility in prostate cancer (CaP). Methods: Total RNA was isolated from 118 tissue specimens from benign prostate hyperplasia (BPH) and CaP patients and a highly sensitive quantitative real-time RT-PCR (qRT-PCR) method for DDC mRNA quantification has been developed using the SYBR Green(R) chemistry. LNCaP prostate cancer cell line was used as a calibrator and GAPDH as a housekeeping gene. Results: DDC was found to be overexpressed, at the mRNA level, in the specimens from prostate cancer patients, in comparison to those from benign prostate hyperplasia patients (p < 0.001). Logistic regression and ROC analysis have demonstrated that the DDC expression has significant discriminatory value between CaP and BPH (p<0.001). DDC expression status was compared with other established prognostic factors, in prostate cancer. High expression levels of DDC were found more frequently in high Gleason's score tumors (p=0.022) as well as in advanced stage patients (p=0.032). Conclusions: Our data reveal the potential of DDC expression, at the mRNA level, as a novel biomarker in prostate cancer. (C) 2008 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.