Pediatric brain tumors: genetics and clinical outcome

In this paper the authors' goal was to investigate the genetic characteristics of primary brain tumors in children and determine their influence on clinical outcome.

The authors performed high-resolution comparative genomic hybridization studies in 14 low-grade and 12 high-grade brain neoplasms in 26 children who underwent surgery between 2005 and 2007.

Complex comparative genomic hybridization alterations were observed in 2 (14.3%) of the 14 lowgrade lesions and in 8 (66.6%) of the 12 high-grade lesions. High-level amplifications of DNA were detected in 3 cases, namely in a desmoplastic medulloblastoma where a c-Myc amplification was found. Gains of 1q were detected in 2 low-grade and 6 high-grade lesions that were classified as ependymomas, astrocytomas, oligodendrogliomas, oligoastrocytomas, and gangliogliomas. When the authors correlated genetics with outcome, they noted that among the low-grade neoplasms only the 2 patients who presented with complex comparative genomic hybridization alterations had to undergo reoperation because of recurrent disease. The patient with c-Myc amplification died of progressive disease. Gains of 1q were only observed in tumor cases with progressive disease.

Complex genetic alterations are indicative of a less favorable outcome in low-grade tumors. In these cases, closer follow-up should be pursued. The authors corroborate that c-Myc amplification is a marker of poor prognosis in medulloblastomas. In this study, they were able to verify that a 1q gain correlates with a poor clinical outcome, independent of tumor grade and histological type. The authors propose that it may be considered a common marker of poor prognosis in these neoplasms.