title: Focal intratumoral heterogeneity for telomerase activity in human prostate cancer.
abstract: OBJECTIVE
  The value of telomerase activity as a marker in clinical decision-making is closely related to how representative the analysis of a small tumor sample is for the whole tumor. We therefore evaluated the intratumoral distribution pattern of telomerase activity in prostatic carcinomas.
  
  
  METHODS
  From 50 prostate cancer patients treated with radical prostatectomy, telomerase activity was determined using the telomeric repeat amplification protocol (TRAP assay). Comparative analysis of at least two separate cancer areas from a single tumor was performed in 42 cases.
  
  
  RESULTS
  Telomerase activation has been demonstrated in 90% of the prostatic carcinomas. Focal intratumoral heterogeneity was found in 38.1% of the tumors with at least two different areas examined. Telomerase positivity of all samples from one given tumor was detected in 50%, telomerase negativity of all samples in 11.9%. A heterogeneous telomerase activity pattern was more frequently detected in tumors with a Gleason score < or = 7 than in those with a Gleason score > 7. Furthermore, there was an increase in the proportion of homogeneously telomerase-positive tumors with increase in severity of the Gleason score. The differences reached statistical significance. Telomerase activity was also detected in non-cancerous prostatic tissue samples.
  
  
  CONCLUSIONS
  Telomerase activation is nearly ubiquitous in prostatic carcinomas, although a heterogeneous telomerase activity pattern within tumors might produce a false-negative result in the telomerase activity assay. This limits the value of telomerase activity assays for diagnostic means. There is evidence for a shift from telomerase-negative prostate cancer tissue toward telomerase positivity during the progression process of prostate cancer. The relatively high proportion of telomerase-positive nonmalignant prostatic tissue samples argues against cancer-specificity of telomerase activation.
authors.affiliation: Clinic of Urology and Pediatric Urology, University of the Saarland, Homburg/Saar, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Wullich
authors.forename: V
authors.initials: V
authors.lastname: Rohde
authors.forename: B
authors.initials: B
authors.lastname: Oehlenschläger
authors.forename: H
authors.initials: H
authors.lastname: Bonkhoff
authors.forename: R
authors.initials: R
authors.lastname: Ketter
authors.forename: T
authors.initials: T
authors.lastname: Zwergel
authors.forename: H P
authors.initials: HP
authors.lastname: Sattler
mesh_terms: D006801:Humans; D008297:Male; D011470:Prostatic Hyperplasia / Q000201:enzymology; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000473:pathology*; D019098:Telomerase / Q000378:metabolism*
chemical_list: D019098:Telomerase