Molecular detection of prostate cells in ejaculate and urethral washings in men with suspected prostate cancer

To determine whether prostatic cells were normally present in ejaculate and if the sensitivity and specificity of the detection of malignant prostate cells in ejaculate and urethral washings from men with suspected prostate cancer could be improved using the more sensitive molecular technique of reverse transcriptase-polymerase chain reaction (RT-PCR).

RT-PCR for prostate-specific antigen (PSA), prostate-specific membrane antigen (PSM) and Apoliprotein D (3 putative prostate-specific and/or cancer-specific markers) was performed on RNA extracts of ejaculate (80) and urethral washings (52) from 77 men with suspected prostate cancer and 12 young controls (<30 years of age) and urines from 5 men who had radical prostatectomies and 10 women.

PSA, PSM and Apolipoprotein D expression was detected in ejaculates and urethral washings from both patient and control groups. No differences were observed in the results obtained for 58 men with suspected or 19 men with confirmed prostate cancer or the 18 vasectomized men within the patient group. Urines from the 5 men who had radical prostatectomies and 10 women were all negative for PSA, but PSM was detected in 2 female urines and in 3 radical prostatectomy samples. As few as 10 LNCaP prostate tumor cells could be detected by PSA RT-PCR when added to female urine.

We have established a sensitive method of detecting prostatic cells in ejaculate and urethral washings and shown that PSA RT-PCR is a reliable indicator of prostate cells in these samples. However, RT-PCR for PSA, PSM and Apoliprotein D were not useful for discriminating malignant from non-malignant prostate cells.