DETECTING HUMAN BLADDER-CARCINOMA CELLS IN VOIDED URINE SAMPLES BY ASSAYING FOR THE PRESENCE OF TELOMERASE ACTIVITY

BAGKGROUND. In an attempt to find a more sensitive and specific noninv asive assay for the detection of bladder carcinoma, the authors assaye d exfoliated cells from patients' voided urine for the presence of tel omerase, an enzyme that maintains a cell's chromosomal length and is t hought to be active in the transformation of normal somatic cells into immortal human tumor cells. METHODS. The authors used a polymerase ch ain reaction (PCR)-based telomeric repeat amplification protocol (TRAP ) assay to determine the presence of telomerase activity in voided uri ne samples from patients with known but yet untreated bladder carcinom a (n = 104) and from patients with hematuria of benign causes (n = 47) . For 88 of the patients with bladder carcinoma, cytology was determin ed independently of the telomerase results or the pathology findings. RESULTS, Of the 104 bladder carcinoma specimens, 88 (85%) tested posit ive for the presence of telomerase. Seventy-nine percent (23 of 29) of the Grade 1 tumors, 84% (32 of 38) of the Grade 2 tumors, and 87.5% ( 28 of 32) of the Grade 3 tumors were positive for telomerase activity. Five patients with carcinoma in situ (100%) were also positive. Telom erase activity was not found in 31 of 47 patients with bladder calculi , benign urethral stricture, benign prostatic hyperplasia, or inflamma tion. In the 16 patients (34%) who did have a false-positive result wh en tested for telomerase, all had either chronic or severe inflammatio n, including 1 patient with an inverted papilloma, 1 patient with cyst itis cystica, and 1 patient with cystitis glandularis. However, for 35 normal, healthy volunteers whose voided urine samples were also assay ed for the presence of telomerase activity, none was found. By compari son, only 51% (45 of 88) of the cytology samples from patients with bl adder carcinoma yielded positive findings, whereas 49% (43 of 88) resu lted in false-negative readings for tumors. Only 13% (3 of 23) of the Grade 1 tumors, 44% (14 of 32) of the Grade 2 tumors, and 82% (23 of 2 8) of the Grade 3 tumors were diagnosed by cytology. AU five patients with carcinoma in situ were positive for cytology as well as for telom erase activity. When cytology was compared with the PCR-based telomera se assay in determining the presence of bladder carcinoma, the differe nce in the overall detection rates (85% for telomerase vs. 51% for cyt ology) was significant (P < 0.001). Furthermore, when telomerase activ ity was compared with cytology for low grade lesions (Grades 1 and 2), the difference in the detection rates (82% for telomerase vs. 31% for cytology) was also significant (P < 0.001).CONCLUSIONS. Urinary cytol ogy yields poor results for low grade tumors. This study shows the pos sible application of the telomerase assay in detecting bladder carcino ma, in particular low grade tumors, in voided urine samples. (C) 1998 American Cancer Society.