HGG-36. ASSESSMENT OF CHROMOSOMAL ABERRATIONS IN DIFFUSE ASTROCYTOMAS OF CHILDHOOD USING THE ARRAY COMPARATIVE GENOMIC HYBRIDIZATION (ACGH+SNP) TECHNIQUE – PRELIMINARY STUDY

Abstract

Abstract BACKGROUND Comprehensive knowledge of the genomic changes underlying cancer is a key basis for diagnosis, prognosis and targeted therapies. With recent advances, the technique of comparative genomic hybridization (aCGH+SNP) facilitates genome-wide screening for genome copy number changes and rapid examination of numerical and structural chromosomal changes, as well as loss of heterozygosity at high resolution down to several tens of kilobases. METHODS The study included 12 patients aged 6 months to 15 years, operated on at the Department of Pediatric Neurosurgery in Krakow due to paediatric-type diffuse gliomas (according to WHO classification 5th Ed). Tumor tissue samples were collected from all included participants as remnants of routine examination. Pangenomic profiling of diffuse astrocytomas was performed with using SurePrint G3 Cancer CGH+SNP Kit 4x180K (Agilent, Santa Clara USA) at the Molecular Genetics Laboratory of the University Children’s Hospital in Krakow. Genomic DNA was extracted automatically from deep-frozen tumor tissue. Descriptive statistics were used to describe the basic characteristics of the data included in the study due to the small number of participants. RESULTS Of the 12 tumors examined by microarray, 5 patients had abnormalities in the form of diffuse high grade gliomas. In 1 patient, only numerical changes in chromosomes were observed, in 1 case only structural chromosomal abnormalities were detected. Combined numerical and structural aberrations were presented in 3 samples. Additionally, we detected 1 case of triploidy and 1 case of loss of heterozygosity. CONCLUSIONS Significant changes were observed in paediatric-type diffuse high-grade gliomas. Interestingly, we detected new undescribed alterations that were not only of a chromosomal nature, but also concerned individual genes. This may constitute the basis for further research aimed at establishing new diagnostic and prognostic markers, as well as effective therapy. A limitation of this study is the small patient sample, and further research is recommended.