Circulating tumor cells as prognostic biological marker in different stages prostate cancer and the effect of different therapeutic approaches on their expression.

BACKGROUND: Circulating tumor cells (CTCs) represent a prerequisite for the formation of metastases. The aim of the study was to identify the role of CTCs as a biological marker of aggressiveness of prostate cancer and verify the expression of molecular markers predictive of response to different therapeutic approaches. METHODS: Prospective, single-arm, non-randomized trial. Twenty-four patients with prostate cancer were enrolled into two groups: group 1 (N.=11) with localized prostate cancer treated with radical prostatectomy; group 2 (N.=13) with metastatic disease. We performed, dosage of blood PSA and testosterone, detection of EGFR, PSMA, PSA and Androgen Receptor (AR) expression on CTC during pre-treatment and follow-up at 1, 3, 9 and 18 months. RESULTS: A total of 65 blood samples were evaluated. In group 1, pre-treatment sampling was negative for the expression of markers on CTC in 90% of the patients while group 2 pre-treatment sampling was positive for the expression of at least one biomarker in seven of 13 patients (54%). After treatment, four patients in group 2 experienced a reduced expression of the markers on CTC, however, in one case there was a new increase of PSA and PSMA at 3 months. One patient had a positivity of AR at 3 months. CONCLUSIONS: The expression of PSA, PSMA, EGFR and AR on CTCs appears to be absent in the pre-treatment samplings in cases of localized prostate cancer. The same markers are hyper-expressed before treatment mostly in metastatic prostate cancer and can relate with early biochemical relapse.