Genome-wide genetic characterization of an atypical meningioma by single-nucleotide polymorphism array-based mapping and classical cytogenetics

Most meningiomas, accounting for about 20% of intracranial tumors, can be cured by surgical removal. Yet, 8-22% of these tumors are classified as atypical or anaplastic (WHO grade II or III, respectively) presenting with a more aggressive behavior and a high relapse rate. We analyzed genomic alterations of an atypical meningioma using high-density single nucleotide polymorphism arrays (SNP-A) karyotyping combined with GTG-banding, multicolor fluorescence in situ hybridization (M-FISH), and locus-specific FISH. In accordance to recent studies applying SNP-A karyotyping in different malignancies we found that genomic lesions are present at a higher frequency than predicted by traditional cytogenetics. Most of these aberrations have not been described before. Additionally, we unveiled loss of heterozygosity (LOH) without copy number changes on chromosome regions 1p31.1, 2p16.1, 2q23.3, 6q14.1, 6q21, 9p21.1, 10q21.1, and 14q23.3, suggesting partial uniparental disomy (UPD). UPDs are currently considered to play an important role in the initiation and progression of different malignancies. Furthermore, we detected two de novo reciprocal translocations, t(8;19)(q24;q13) and t(10;16)(q22;q12.1). While GTG-banding and M-FISH data suggested balanced translocations, SNP-A analysis clearly demonstrated imbalances in the same region.