According to the World Health Organization
gangliogliomas are classified as well-differentiated and slowly growing
neuroepithelial tumors, composed of neoplastic mature
ganglion and glial cells. It is the most frequent
tumor entity observed in patients with long-term
epilepsy. Comprehensive cytogenetic and molecular cytogenetic data including high-resolution genomic profiling (single nucleotide polymorphism (SNP)-array) of
gangliogliomas are scarce but necessary for a better oncological understanding of this
tumor entity. For a detailed characterization at the single cell and cell population levels, we analyzed genomic alterations of three
gangliogliomas using
trypsin-Giemsa banding (GTG-banding) and by spectral karyotyping (SKY) in combination with SNP-array and gene expression array experiments. By GTG and SKY, we could confirm frequently detected
chromosomal aberrations (losses within chromosomes 10, 13 and 22; gains within chromosomes 5, 7, 8 and 12), and identify so far unknown genetic aberrations like the unbalanced non-reciprocal translocation t(1;18)(q21;q21). Interestingly, we report on the second so far detected
ganglioglioma with ring chromosome 1. Analyses of SNP-array data from two of the
tumors and respective germline
DNA (peripheral blood) identified few small gains and losses and a number of copy-neutral regions with loss of heterozygosity (LOH) in germline and in
tumor tissue. In comparison to germline
DNA,
tumor tissues did not show substantial regions with significant loss or gain or with newly developed LOH. Gene expression analyses of
tumor-specific genes revealed similarities in the profile of the analyzed samples regarding different relevant pathways. Taken together, we describe overlapping but also distinct and novel genetic aberrations of three
gangliogliomas.