Telomerase activity - Simplification of assay and detection in bladder tumor and urinary exfoliated cells

Detection of telomerase activity can differentiate malignant from benign ce lls. However, the original telomeric repeat amplification protocol (TRAP) m ethods had a number of limitations including a radioisotope labeling [alpha (32)P] dCTP [alpha(32)P] dGTP system. We developed digoxigenin labeled CX p rimer to detect telomerase activity without using radioisotope and attempte d to detect telomerase activity of bladder tumor and exfoliated cells in bl adder cancer patients. Telomerase activity was detected in 5 (71%) of 7 pat ients diagnosed with grade 1, 31 (97%) of 32 grade 2, and 11 (100%) of 11 g rade 3 bladder tumors. In urinary exfoliated cells, 32 (82%) of 39 grades 1 or 2 bladder tumors were positive for telomerase activity but 20 (51%) of 39 were positive for urinary cytology (P < 0.01). Ten (91%) of ii of grade 3 tumors were positive for telomerase activity and 11 (100%) of 11 were pos itive urinary cytology. Three of 100 noncancerous patients were positive fo r telomerase activity. Sensitivity, specificity, and positive predictive va lue of telomerase activity assay in urinary exfoliated cells were 84%, 97%, and 93%, respectively. Telomerase activity may be a useful diagnostic mark er to detect the existence of immortal cancer cells in the urine. (C) 1999 Elsevier Science Inc. All rights reserved.