[Detection of telomerase activity by semi-quantitative and in situ assays and quantification of hTERT expression in...

Several studies have reported the important role played by telomerase, an enzyme which maintains the length of telomeres, during carcinogenesis. The objective of this study was to detect telomerase activity by semiquantitative in situ methods and to quantify expression of the hTERT subunit in a group of bladder cancers in order to assess its diagnostic and prognostic value.

Telomerase activity (TA) was detected by the TRAP method ("telomeric repeat amplification protocol") on a series of 29 bladder cancers and 3 samples of healthy mucosa. Levels of expression of the hTERT gene were studied by real-time quantitative RT-PCR. In situ detection of TA was performed by using the same kit as the TRAP method, applied to frozen tissue sections exclusively for cases with discordant results between TA detection and hTERT mRNA.

TA was detected by TRAP in 15 of the 29 bladder cancers. hTERT mRNA was detected and quantified in all tumour samples. A significant correlation was observed between TA and the level of hTERT mRNA expression. In situ detection of TA demonstrated heterogeneous TA in tumour tissue. A significant correlation was observed between the level of hTERT mRNA expression and tumour histological grades and stages.

hTERT mRNA detection by real-time quantitative RT-PCR appears to be a sensitive method for the diagnosis of bladder cancer with a good correlation with tumour grade and stage. Quantitative evaluation of hTERT mRNA could therefore be a useful marker of tumour progression for the early diagnosis and follow-up of bladder cancers.