Expression of the RNA component of human telemorase (hTR) in ThinPrep (R) preparations from bladder washings

BACKGROUND. The enzyme telomerase is associated with cellular immortality a nd is expressed in the vast majority of human neoplasms. The expression of the RNA component of human telomerase (hTR) shows excellent concordance wit h enzyme activity. METHODS. In this study, hTR expression was analyzed in a series of 18 perio perative bladder washings and compared with histologic diagnoses from mater ial obtained in the same setting. The hTR expression analysis used an S-35- based in-situ hybridization assay. ThinPrep(R) preparations fixed in Preser vCyt(R) solution (Cytyc Corporation, Boxborough, MA) were hybridized with s ense and antisense hTR probes. A 1-4+ grading scheme was used, with appropr iate positive and negative controls. RESULTS. Five of six (83%) lesions with benign histology had hTR expression that was 2+ or less in the exfoliated urothelial cells. In contrast, 11 of 12 (93%) lesions with malignant histology had an hTR expression that was f ocally 3+ or more, with 7 of 12 (58%) lesions having 4+ hTR expression in a t least some urothelial clusters. Although increased hTR expression was pre sent in smears with malignant urothelial cells, a similar trend was not see n with muscularis propria invasion or higher grades of TCC on subsequent hi stology. CONCLUSIONS. The use of in situ hybridization technique bypasses the need f or stringent specimen processing and allows identification of the specific cell type that expresses telomerase. Cancer (Cancer Cytopathol) 2001;93:73- 79. (C) 2001 American Cancer Society.