Molecular analysis of prostate cancer: prostate tissue and urine proteomics based approach

Benign prostatic hyperplasia (BPH) and prostate cancer are the most frequently diagnosed conditions in men above 60 years. BPH manifests as benign enlargement of the prostate gland causing pain and difficulty in micturition, often associated with other lower urinary tract symptoms. On the other hand, prostate cancer might initially set in as a tumor of no clinical significance, but can ultimately develop into an aggressively metastatic cancer at later stages. Due to overlapping symptomatic manifestations with BPH, it might be difficult to diagnose prostate cancer and differentiate it from BPH. Screening for prostate cancer is based on examining the levels of prostate specific antigen (PSA), a clinical biomarker for prostate cancer in blood. However, several reported cases indicate that PSA might lack the sensitivity and specificity required to differentiate between the cancerous and benign conditions of prostate. Therefore, in the absence of non-invasive biomarkers in a diagnostic setup, an intensely invasive surgical removal of a part of the tissue and subsequent histopathologial examination is the only available procedure to confirm the cancer. In this study, we used tissue and urine proteomics platforms to profile respective proteomes in both clinical conditions. We observed that latent transforming growth factor binding protein was significantly under-expressed in the both tissue and urine proteome of prostate cancer. We propose that the down-regulation of the latent transforming growth factor binding protein 4 might be explored in a large set of patients with prostate cancer to develop a non-invasive urine based biomarker for the diagnosis of prostate cancer.