It is rare that a GIST tumor harbors mutations in both KIT and PDGFRA, simultaneously; however, one GIST case (S09) carries two GIST driver mutations located in exon 11 of KIT (c.T1676C, p.V559A) and in exon 18 of PDGFRA (c.A2525T, p.D842V). The gene discussed is KIT; the disease is neoplasm.