As previously mentioned, PTBP1 regulates the AS of multiple target genes, among these are fibroblast growth factor receptor-1 (FGFR-1), pyruvate kinase M (PKM), and multidrug resistance protein 1 (MRP1) [49], contributing to the drug-resistant phenotype frequently associated with GBM [50]. Here, FGFR1 is linked to glioblastoma.