Medulloblastoma: Does the Isochromosome 17q Influence on the Long Term Survival?

ABSTRACT

OBJECTIVE: An isochromosome for the long arm of 17, i(17q), is the most frequent chromosomal abnormality in medulloblastoma, occurring in 30-60% of cases by karyotype analysis and this abnormality has been reported to be present in cases with a shorter survival time by some authors. Moleculogenetic analysis for i(17q) was performed to identify its influence on the long term survival. PATIENTS AND METHODS:The authors reviewed 17 children and divided them into two groups(favorable and poor outcomes) to elucidate the influence of the i(17q) on the long term survival. Eight children with favorable outcome are in disease-free status during the follow-up period (range 52-87 months, median 66 months). The other nine children with poor outcome died of disease progression or recurrence and their median survival time was 13 months (range 1-28 months). Fluorescent in situ hybridization(FISH) was used for the detection of i(17q) in 17 children. RESULTS: The i(17q) was detected in nine of 17 children. There was no difference in the positive rates of i(17q) between two groups. CONCLUSION: The i(17q) was detected by FISH in 53% of medulloblastoma patients. Presence of the i(17q) was not a prognostic factor on the long term survival.