Telomerase activity and telomerase subunits gene expression patterns in neuroblastoma: A molecular and immunohistochemical study establishing prognostic tools for fresh-frozen and paraffin-embedded tissues

Purpose: We have recently demonstrated that telomerase activity (TA) is an independent prognostic factor in neuroblastomas. in the present study, the prognostic impact of TA and gene expression of the three major telomerase s ubunits is evaluated by molecular and immunohistochemical techniques in fre sh-frozen and paraffin-embedded tissues. Patients and Methods: One hundred thirty-three neuroblastomas of all stages were analyzed for TA, The TA levels of 75 neuroblastoma cases were correla ted with gene expression of telomerase subunits hTRT, human telomerase RNA (hTR), and telomerase protein 1 (TP1) by quantitative reverse transcriptase polymerase chain reaction (RT-PCR), using an innovative approach on the Li ghtCycler instrument (Roche Diagnostics, Mannheim, Germany). For selected c ases, the applicability of RT-PCR and immunohistochemistry for hTRT express ion analysis was investigated in paraffin-embedded tissues. TA and subunit expression patterns were correlated with traditional prognostic indicators and disease outcome. Results: TA was present in a total of 39 (29.3%) of 133 neuroblastomas and in 31 (29.8%) of 104 initial neuroblastomas without cytotoxic pretreatment, TA was significantly correlated with both event-free and overall survival (P <.0001), Furthermore, we found a significant correlation between express ion levels of TA and hTRT (P <.0001) as well as hTR (P <.001), Multivariate analysis revealed only TA and tumor stage but not serum lactate dehydrogen ase, MYCN amplification, or age at diagnosis as independent prognostic fact ors. Conclusion: The significant correlation with clinical outcome strongly reco mmends that analysis of TA be incorporated into the clinical investigation of each individual neuroblastoma at the time of diagnosis. Because the mere presence or absence of TA without further quantification is sufficient bas is for predicting disease outcome, the telomeric repeat amplification proto col assay could be complemented with but not replaced by analysis of hTRT o r hTR expression. J Clin Oncol 18:2582-2592, (C) 2000 by American Society o f Clinical Oncology.