Multiomics approach showing genome-wide copy number alterations and differential gene expression in different types of North-Indian pediatric brain tumors

Abstract

PurposeBased on copy number alterations and transcriptional profiles, the posterior fossa tumors (medulloblastoma (MB), ependymoma and pilocytic astrocytoma) have been classified into various subgroups. The study design was aimed to identify and catalog genome-wide copy number alterations and differential gene expression in different types of North-Indian pediatric posterior fossa tumors and matched control tissue through Molecular Inversion Probe (MIP) Based and Human Transcriptome Array. Experimental designMIP based OncoScan Array and Human Transcriptome Array 2.0 were used to molecularly-categorize histopathologically and immunohistochemically proven tumor samples on the basis of copy number variations and altered gene expression patterns and/or alternative splicing events. ResultsBased on molecular, histopathological/immunohistochemical and age-dependent factors MB was subgrouped into group-3 MB, Wnt and SHH; ependymoma into balanced, numerical and structural/anaplastic; and pilocytic astrocytoma was stratified age-dependently. Compared with the vermis tissue of MB, the vermis tissue of ependymoma showed higher levels of gain and losses compared with their counter tumor parts implicating metastasis within the confined region. Group-3 MB and anaplastic ependymoma represented highest differentially expressed genes both at gene and exon levels in the CN altered regions compared with other subgroups of MB and ependymoma respectively. ConclusionThis multiomics approach based molecular characterization of posterior fossa tumors together with clinical and histopathological factors may help us in the area of personalized medicine.