Expression of matrix metalproteinasa enzyme 2 (MPM-2) in prostate cells in blood circulation (CPCS) in men with prostate cancer: an immunocytochemistry study

Objective: Matrix metalloproteinase-2 is a gelatinase implicated in the metastatic process. Cells expressing MMP-2 can cross the extracellular matrix and disseminate to other tissues. We present a study of MMP-2 express of circulating prostate cells in men with prostate cancer. Methods and Patients: A prospective, multicenter study of men with prostate cancer attending the Hospital de Carabineros de Chile, INRAD and the Instituto de BioOncología between 2006 and 2008. After written informed consent a 4 ml blood sample was taken, mononuclear cells were obtained using differential centrifugation and CPCs identified using immunocytochemistry. Positive samples with PSA staining cells underwent a second process with anti-MPM-2. Age, clinical stage, serum PSA were noted for each patient. Results: 105 patients entered the study, 30 pre-treatment and 75 post treatment, with an average age of 71.3 +/- 8.4 years. There was an association with CPC detection frequency with clinical stage and Gleason score. All CPCs expressed MMP-2. Conclusions: The results indicate that MMP-2 expression is important in the dissemination of primary and secondary prostate cancer cells, that there is no association between prognostic factors and MMP-2 expression in CPCs. The presence of CPCs does not imply the presence of micrometastasis nor origin of dissemination in the case of 2nd CPCs but the presence implies a higher risk of micrometastasis. The detection of these cells could be a useful tool in the follow up of patients with prostate cancer.