[Expression of P504S and matrix metalloproteinase-2 in circulating prostate cells disseminated as a result of transrectal ultrasound guided biopsy as determined by immunocytochemistry: Clinical implications].

Objectives: Surgical manipulation of cancer has been shown to increase blood borne cancer cell dissemination and increase the risk of metastasis. We present the effect of prostate biopsy on prostate cell dissemination and the phenotypic characteristics of these cells.

Methods: 50 men undergoing initial prostate biopsy for suspicion of prostate cancer were studied. Blood samples were taken immediately before, and 1 and 24 hours after biopsy for circulating prostate cells (CPC) determination and phenotypic characterization. CPCs were detected and counted using standard immunocytochemistry using anti-PSA and then characterized using anti-P504S and anti-matrix metalloproteinase-2 (MMP-2).

Results: 14 (28%) men had cancer detected on biopsy. 13/14 had P504S (+) and MMP-2 (+) cells detected prior to biopsy. One hour after biopsy there was a mixture of P504S (+) and P504S (-) cells detected, as well as MMP-2 (+) and MMP-2 (-) cells detected. 24 hours after biopsy the same 13/14 men remained positive, although the number of CPCs increased 1 hour after biopsy and then the numbers decreased to pre-biopsy levels after 24 hours. In cancer negative men, P504S (-) and MMP-2 (-) cells were detected, some of these cells persisted 24 hours after biopsy.

Conclusions: Prostate biopsy causes dissemination of prostate cells into the circulation, both malignant and benign; the majority of them are cleared within 24 hours. There was no conversion of negative to positive result in men with cancer, this suggests that the inherent capacity of malignant CPCs to disseminate is more important than the effect of dissemination caused by prostate biopsy.