OBJECTIVES: To investigate tumour tissue and non-malignant tumour-surrounding bladder mucosa (NTSBM) for expression of human telomerase RNA (hTR) as a possible marker for premalignant transformation of urothelial cells. MATERIAL AND METHODS: From 67 patients with superficial transitional cell carcinoma (TCC), sections with representative tumour tissue and NTSBM were selected for evaluation. Sections with moderate or severe dysplasia were omitted from evaluation. hTR expression was detected with in situ hybridization using a 35S-UTP-labelled riboprobe, and analysed semiquantitatively by counting the hybridization signals. RESULTS: In 45 of the 67 patients hTR expression was moderate or strong in tumour tissue, and in 20 hTR expression was moderate or strong in NTSBM. Moderate or strong hTR expression was detected in the NTSBM from 19 of 60 patients with pTa/pT1 tumours. Of the 56 patients who were treated conservatively, eight had tumour recurrence, of whom five had moderate or strong hTR expression in the TSBM, compared with only 14 of 48 patients without tumour recurrence. CONCLUSION: Detecting hTR expression and the morphological distribution of hTR hybridization signals in NTSBM by in situ hybridization might indicate premalignant alterations involved in tumour recurrence.
