Circulating Prostate Cells Found in Men with Benign Prostate Disease Are P504S Negative: Clinical Implications

Introduction. Developments in immunological and quantitative real-time PCR-based analysis have enabled the detection, enumeration, and characterization of circulating tumor cells (CTCs). It is assumed that the detection of CTCs is associated with cancer, based on the finding that CTCs can be detected in all major cancer and not in healthy subjects or those with benign disease. Methods and Patients. Consecutive men, with suspicion of prostate cancer, had blood samples taken before prostate biopsy; mononuclear cells were obtained using differential gel centrifugation and CPCs detecting using anti-PSA immunocytochemistry. Positive samples underwent further classification with anti-P504S. Results. 329 men underwent prostate biopsy; of these men 83 underwent a second biopsy and 44 a third one. Of those with a biopsy negative for cancer, 19/226 (8.4%) had CPCs PSA (+) P504S (？) detected at first biopsy, 6/74 (8.1%) at second biopsy, and 5/33 (15.2%) at third biopsy. Men with cancer-positive biopsies did not have PSA (+) P504S (？) CPCs detected. These benign cells were associated with chronic prostatitis. Conclusions. Patients with chronic prostatitis may have circulating prostate cells detected in blood, which do not express the enzyme P504S and should be thought of as benign in nature. 1. Introduction Although the first report on circulating tumors was published by Ashworth in 1869 [1], the lack of technology precluded further investigations on their clinical use until recently. Developments in immunological and quantitative real-time PCR-based analysis have enabled the detection, enumeration and characterization of circulating tumor cells (CTCs). The monitoring of CTCs has the potential to improve therapeutic management at an early stage and also to identify patients with increased risk of tumor progression or recurrence before the onset of clinically detected metastasis. Furthermore, the molecular profiling of CTCs can provide new insights into cancer biology and systemic treatment in neoadjuvant or adjuvant settings. It is assumed that the detection of CTCs is associated with cancer, based on the finding that CTCs can be detected in all major cancers and not in healthy subjects or those with benign disease [2]. Most of the assays are based on enrichment and subsequent identification of CTCs using monoclonal antibodies directed against epithelial epitopes, for example, the transmembrane glycoprotein epithelial cell adhesion molecule (EpCAM) or cytokeratins that are expressed on both normal and malignant cells. This widely based approach is based on the