FGFR1 and central nervous system cancer: Implementation of single cell RNA sequencing (scRNA-seq) to glioma studies showed the considerable intratumoral genetic heterogeneity and mosaic expression of genes coding for surface receptors and ligands, including EGFR, PDGFRA, PDGFA, FGFR1 (fibroblast growth factor receptor 1), FGF1 (fibroblast growth factor 1), NOTCH2 (notch receptor 2), and JAG1 (jagged canonical notch ligand 1) [11].