Telomerase expression as complementary prognostic factor in neuroblastoma.

Background: Neuroblastoma (NB) is an aggressive tumor of childhood with a highly heterogeneous course. Identification of standard prognostic factors has several limitations. Hence, there is an increasing demand to identify new prognostic factors and tools that help in risk stratification of patients for proper treatment.

Objective: To assess the prognostic and predictive impact of quantitative telomerase expression in NB patients.

Methods: We investigated quantitative telomerase expression by immunohistochemistry in 44 neuroblastoma patients. Results were correlated with standard prognostic factors, n-myc amplification by chromogen in situ hybridization (CISH) and patients' response to treatment and survival.

Results: High telomerase expression and n-myc expression were reported in 52.3% and 56.8% ; respectively. There was a significant relation between telomerase expression and n-myc amplification. Stage 3 and 4 represented 91% of patients. Thirteen patients showed complete remission, 9 partial remission, 19 no response and 3 showed progressive disease. The median followup was 3 years with 80% overall and 72% progression free survival for the low teleomerase expression group; and 52.2% and 55.4% for high teleomerase expression group. High Telomerase expression by immunohistochemistry was significantly associated with n-myc amplification and with poor response to treatment with a trend toward lower overall and progression free survival.

Conclusions: Telomerase expression by immunohistochemistry is a simple potential tool for risk stratification of NB patients. CISH can serve as a readily available alternative simple tool, compared to FISH, in identifying neuroblastoma cases with abnormal n-myc gene copy number.

Key Words: Telomerase expression- N-myc amplification- Prognosis- Neuroblastoma.