Targeted resequencing for analysis of gene mutations in pediatric Glioblastoma Multiforme

Glioblastoma multiforme (GBM; WHO-grade IV), the most frequent primary malignant brain tumor in adults, accounts for approximately 7-9% of all central nervous (CNS) tumors in childhood. Adult and paediatric GBMs (pGBMs) have distinct genetic and molecular pathways of tumorigenesis and different studies, based on array-CGH analysis, reported that there are significant differences in Copy Number Alterations (CNA). In our previous study we identified, using array-CGH, recurrent CNA in 8 pGBMs establishing minimum common regions (MCR) of duplication/amplification and deletion. Based on these results, we developed a next-generation sequencing (NGS) approach to screen the genetic profile of tumors. NGS has provided a new paradigm in biomedical research to delineate the genetic basis of human diseases. The panel was designed to cover 420 genes selected within of MCRs to try to identify new genes involved in tumorigenesis and/or progression of pGBMs. In 8 patients we found 18 heterozygous mutations in different genes. The same mutations were also found in DNA extracted from blood and in two cases we demonstrated the parental origin of 12 mutations. Given the rarity of the disease and the scarcity of data in the literature, our findings may better elucidate if there is a genomic background in development and progression of pGBM. The recognition of candidate genes underlying this disease could then improve treatment strategies for this devastating tumor