Association between gene fusions and copy number changes in the TCGA dataset. A. Distribution of each fusion mechanism over three chromosomes (7, 12 and 1) with most fusions. Majority of fusions due to focal amplifications (68%) are found on chromosome 7. Fusions formed due to complex genomic rearrangements are mostly present on chromosomes 12 and 7. B. Fusion without associated copy number changes. C. Fusion points within a genomic amplicon. D. Fusions due to tandem duplications. E. Black arc showing fusion due to interstitial genomic deletion. F. Fusions due to complex genomic rearrangements. G. Inter-chromosomal fusion with at least one fusion point near a genomic breakpoint. H. Distribution of fusion mechanisms for 175 fusion sequences. Eight percent of the fusion sequences do not have associated copy number changes. Forty percent of fusion sequences are formed by complex genomic rearrangements. Fusions in the proneural subtype are mostly formed by complex genomic rearrangements.