PDGFRA and chordoma: Furthermore, chordoma samples repeatedly show increased expression of, amplifications in or possibly activating mutations in several RTK genes, including EGFR and the chromosome 4q12 genes VEGFR2 (KDR), KIT and PDGFRA that relay their activity through Ras (Akhavan-Sigari et al., 2014a,b,c; de Castro et al., 2013; Fischer et al., 2015; Miettinen et al., 2012; Tamborini et al., 2006).