The use of telomerase activity for the detection of prostatic cancer cellsafter prostatic massage

Purpose: Prostate cancer is the most commonly diagnosed cancer in the Unite d States. The diagnosis or followup of prostate cancer in men older than 50 years is based on digital rectal examination, measurement of the free-to-t otal prostatic specific antigen ratio and transrectal ultrasound assisted n eedle biopsy of the prostate. We developed and evaluated a noninvasive meth od for diagnosing prostate cancer based on the measurement of telomerase ac tivity after prostatic massage in fresh voided urine or after urethral wash ing. Materials and Methods: We obtained 36 specimens of cells after prostatic ma ssage in the fresh voided urine of 16 patients who subsequently underwent r adical prostatectomy and after urethral washing in 20 who underwent prostat e needle biopsies, Ethylenediaminetetraacetic acid was immediately added to the collected urine or washing to a final concentration of 20 mM. After pr otein extraction by CHAPS buffer each specimen was tested for telomerase ac tivity in a 2-step modified telomeric repeat amplification protocol assay. The 2 prostate cancer cell lines PC-3 and LNCaP with high telomerase activi ty were used as a positive control. Results: Telomerase activity was detected in 14 of 24 samples with known pr ostate cancer (sensitivity 58%). In contrast, no telomerase activity was fo und in the 12 cases without histological evidence of prostate tumor (specif icity 100%). Eight of 9 poorly differentiated cancers expressed telomerase activity (89%), while only 6 of 15 well and moderately differentiated cance rs showed telomerase activity (40%). Conclusions: Our data illustrate that telomerase activity may be detected i n voided urine or washing after prostatic massage in patients with prostate cancer. Sensitivity was higher for poorly differentiated tumors. This appr oach is not currently available for detecting prostate cancer in clinical p ractice. However, these results are promising and further studies are ongoi ng.