Abstract Genome instability and structural rearrangement is a distinctive hallmark of the cancer genome. With next-gen sequencing technologies, our ability to measure structural rearrangements that occur throughout tumorigenesis and progression has improved significantly, while creating an urgent need for rearrangement discovery, analysis, and visualization methods to aid in our understanding of these events. We have developed a sequencing analysis pipeline that streamlines the discovery of an individual tumor's mutations, small indels, copy number alterations, allele-specific amplifications and deletions, and genomic rearrangements. Rearrangements are refined to base-pair precision using unmapped, putative split reads found in the vicinity of the breakpoint. Results are presented in an interactive, web-based genome browser that provides analysis and visualization of both high-level, processed results as well as the raw data from which they were derived. From the web-based interface, results from multiple samples can be aggregated into user-defined sample cohorts to help identify features that are shared among a significant number of the samples. Using this sequencing analysis pipeline, we discovered high-confident, small- and large-scale somatic events in 17 whole genome glioblastoma multiforme (GBM) tumor samples from The Cancer Genome Atlas (TCGA) project, using their matched normal sequences to filter out germline variants. Among many interesting structural aberrations identified in these samples, we find four samples exhibiting EGFR amplifications and the presence of the EGFRvIII mutant, characterized by the in-frame deletion of exons 2-7 to produce a constitutively active form of the receptor. Comparing the read support of the EGFRvIII-associated breakpoints to the number of normally-mapped reads in the neighborhood suggest that, in all cases, the EGFRvIII mutant emerges after the amplification of wild-type EGFR, existing as a small fraction of total number of EGFR copies. In other samples, evidence of high copy number amplicons containing both MDM2 and EGFR are discovered at detectable levels in the blood sequencing data, raising the possibility that patient-specific PCR-based assays could be developed to quantitate the presence of somatic rearrangements as a proxy to monitor the progression of brain tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3982. doi:1538-7445.AM2012-3982