PTBP1 and glioblastoma: Investigating the inclusion level (measured as percent-spliced-in (PSI) across transcripts covering the respective genomic regions) of exons having predicted binding sites for the PTBP1, the RBFOX RBPs, or for both RBPs within the MAPP-inferred regions, we found that cassette exons that are coregulated by both RBPs exhibit the largest differences in PSI when comparing glioblastoma to normal brain tissue (Fig. 5a).