Chromosomal imbalances in primary oligodendroglial tumors and their recurrences: clues about malignant progression detected using comparative genomic hybridization

Abstract

Object. Despite the rapid increase in knowledge concerning the genetic basis of malignant progression in astrocytic tumors, progression of oligodendroglial tumors (including both pure oligodendrogliomas and mixed oligoastrocytomas) is still poorly understood. The aim of the present study is the elucidation of chromosomal imbalances involved in the progression of oligodendroglial tumors toward malignancy. Methods. Using comparative genomic hybridization (CGH) on snap-frozen tumor tissue, the tumor genomes of five primary oligodendroglial tumors and associated recurrent tumors were screened for chromosomal imbalances. This information was correlated with clinical data (including follow-up data) and histopathological malignancy grade. In all cases an increase in chromosomal imbalances was detected in the recurrent tumor, indicating genetic progression. In three of the five cases this correlated with malignant progression detected at the histopathological level. The results indicate that, similar to what occu...