Objective: The aim of this study was to establish the specific detection of prostasin-expressing prostate cells in the blood of patients with prostate cancer.
Patients and methods: A prostasin-specific RT-PCR assay was developed and optimized using limiting dilutions of cell line LNCaP mixed with normal blood specimens. Then, it was used to examine peripheral blood samples from 96 patients with prostate cancer (localized carcinoma, n = 69, metastatic, n = 27). Specificity was assessed by examination of 86 negative controls (healthy individuals, n = 47, benign prostate hyperplasia, n = 17, nonprostate cancer patients, n = 22).
Results: All 86 control samples failed to amplify the specific 546-bp prostasin PCR products. Blood samples from 35 out of 96 (36%) prostate cancer patients were found positive. In metastatic patients, 63% (17/27) scored positive whereas in localized adenocarcinoma prostasin primers detected prostate cells in 26% (18/69).
Conclusion: Our results that approximately 30% of patients with localized prostate cancer scored positive for prostasin-specific RT-PCR confirm that the hematogenous spillage of prostate cells is an early event in the natural history of prostate cancer. As none of our negative controls were found positive, we conclude that blood-borne RT-PCR amplification of prostasin transcripts may lead to an earlier diagnosis of disseminated disease in patients with organ-confined carcinoma. The clinical significance of prostate cell detection and the potential applications of this new tool aside or along prostate-specific antigen or prostate-specific membrane antigen RT-PCR require longer-term follow-up.