NEW ORLEANS--The enzyme telomerase is detectable in the majority of bladder washings from patients with bladder cancer, making it a reliable marker for cancer, according to several reports presented at the American Urolog-ical Association (AUA) annual meeting.
Telomerase is thought to be responsible for maintaining telomere in tumors, allowing cancer cells to avoid programmed cell death. It has been found in up to 90% of all cancers tested.
The Society for Urologic Oncology's Clinical Research Award was presented to Drs. Elizabeth Kavaler and Brian Liu, of Mt. Sinai Medical Center, New York, together with other Mt. Sinai investigators led by Dr. Michael J. Droller, professor and chairman of urology, for their research in this area.
The investigators used PCR-based telomeric repeat amplification (TRAP) to detect telomerase in voided samples from 57 patients with bladder cancer. They found telomerase activity to be very useful in diagnosing low-grade bladder cancer, much more so than cytology readings from the same samples.
Of the 57 samples, 52 (91%) tested positive for telomerase. This included 100% of the grade 1 tumors, 92% of the grade 2 tumors, and 83% of the grade 3 tumors. Two patients with carcinoma in situ were also positive for telomerase, Dr. Kavaler reported.
In contrast, telomerase was not found in samples from 23 of 30 patients with other urinary disorders. Furthermore, it was present in 21 of 41 bladder cancer samples for which cytology had yielded a false-negative reading for tumor. Cytology diagnosed none of the grade 1 tumors, 39% of the grade 2 tumors, and 78% of the grade 3 tumors.
German investigators evaluated the test in 75 tissue samples, 40 bladder washings, and 36 urine samples taken from patients with urothelial carcinoma of the bladder. Eight tissue samples were taken from normal urothelium.
The researchers detected telomerase activity in 96% of the tissue samples from patients with histologically confirmed cancer. No normal tissue samples showed telomerase activity.
Telomerase activity was also found in 73% of the bladder washings from cancer patients, and there were no false-positive results, Dr. Marcus Muller, of Benjamin Franklin University Hospital, Berlin, reported.
A report from Seoul, Korea, found telomerase activity in tissue and bladder washings in 96% of cases of bladder transitional cell carcinoma. Cytologic analysis diagnosed 70% of the cancers and missed all but one case of grade 1 disease, Dr. Dong-hyeon Lee, of Yonsei University, reported.
In a study from Madigan Army Center, Tacoma, Washington, all 22 solid transitional cell bladder carcinomas exhibited telomerase activity, while eight of 10 benign urothelial specimens did not. Telomerase activity was identified in 80% of bladder washings from patients with histologically confirmed cancer, including 75% of those with in situ tumors.
Telomerase activity was not detected in 66% of control subjects with normal cystoscopy. About 30% of the false-positive cases were found to have urothelial atypia, Dr. Raymond S. Lance reported.