PTBP1 also regulates reticulon 4 (RTN4) exon 4 exclusion, leading to an increase in RTN4-B isoforms, the isoform widely expressed in human tissues, thereby promoting endothelial cell migration and vascular remodeling.192 In GBM, RTN4-B isoform expression is upregulated, causing EMT, vascular proliferation, and migration activity.95 Recently, a unique feedback mechanism between PTBP1 and BRG1-associated factor 45D (BAF45D) was discovered. Here, PTBP1 is linked to glioblastoma.