Detection of circulating tumor cells in patients with prostate cancer

The utility of nested reverse transcriptase-polymerase chain reaction (RT-PCR) was examined by using as primers the prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSM) markers for prostate cancer staging. This method allows detection of a small number of cells expressing the human PSA or PSM gene, even when these cells are extensively diluted in a population of non PSA or PSIA expressing cells. This method was performed on 25 patients with prostate cancer. Six patients had the RT-PCR for PSA or PSM negative. Four patients were positive on the PSA and negative on the PSM; these patients were without progression. Fifteen patients were tested positive on both markers. In twelve of them the progression of cancer took place and six of these 12 (50%) died within two years. The aim of this study was to test if PSA and PSM are good prognostic markers for monitoring the metastasing process in prostate cancer.