Detection of telomerase activity in prostatic fluid specimens

We report here the extended use of the telomeric repeat amplification protocol (TRAP) assay for the detection of telomerase activity in fresh prostatic fluid obtained from anesthetized patients. Telomerase activity was detected in pellet extract and/or supernatant fluid of specimens obtained from 25 of 30 prostate cancer (PCa) patients (83%), whereas no activity was similarly detectable in specimens taken from 8 of 9 patients (89%) without clinical evidence of PCa. The positive predictive value (PPV) of the TRAP assay for PCa in this pilot study was 96%. We found a strong correlation between telomerase activity in prostatic fluid specimens and serum prostate specific antigen (PSA) values. Telomerase activity was found in 84% of specimens from patients with PSA values >4 ng/ml, whereas in specimens from patients with PSA values ⩽4 ng/ml, only 29% tested positive for telomerase activity. In patients with PSA values above the standard 0 to 4 ng/ml reference range, the PPV of the TRAP assay was 84%. Furthermore, telomerase activity could be detected in 85% of the specimens from PCa patients with Gleason scores >4. In prostatic fluid from PCa patients with Gleason scores of ⩽4, telomerase activity was detected 50% of the time. The PPV was 92% when a Gleason score of 4 was used as the lower limit. This pilot study raises the possibility of utilizing telomerase activity as an aid in PCa detection.