Molecular cytogenetic analysis of chromosomal aberrations in cells of low grade gliomas and its contribution for tumour classification
Abstract
Low-grade gliomas represent a heterogeneous group of primary brain malignancies. The current dia-gnostics of these tumors rely strongly on histological classification.
With the development of molecular cytogenetic methods several genetic markers were described, conributing to a better distinction of glial subtypes. The aim of this study was to assess the frequency of acquired chromosomal aberrations in low-grade gliomas and to search for new genomic changes associated with higher risk of tumor progression.
Patients and Methods: We analysed bio-psy specimens from 41 patients with histological dia-gnosis of low-grade glioma using interphase fluorescence in situ hybridization (I-FISH) and single nucleotide polymorphism (SNP) array techniques (19 females and 22 males, medium age 42 years). Results: Besides notorious and most frequent finding of combined deletion of 1p/19q (81.25% patients) several other recurrent aberrations were described in patients with oligodendrogliomas: deletions of p and q arms of chromosome 4 (25% patients), deletions of the short arms of chromosome 9 (18.75% patients), deletions of the long arms of chromosome 13 and monosomy of chromosome 18 (18.75% patients).
In bio-psy specimens from patients with astrocytomas, we often observed deletion of 1p (24% patients), amplification of the long arms of chromosome 7 (16% patients), deletion of the long arm of chromosome 13 (20% patients), segmental uniparental disomy (UPD) of the short arms of chromosome 17 (60% patients) and deletion of the long arms of chromosome 19 (28% patients). In one patient we detected a shuttered chromosome 10 resulting from chromothripsis.
Conclusion: Using a combination of I-FISH and SNP array, we detected not only known chromosomal changes but also new or less frequent recur-rent aberrations. Their role in cancer-cell progression and their impact on low-grade gliomas classification remains to be elucidated in a larger cohort of patients.