<prompt> Commonest mutations that are associated with GIST are inPlatelet-derived growth factor receptor aTyrosine kinase KITBRAFNRAS  <response>: Approximately 75 to 80 of all GISTs have oncogenic, gain-of-function mutations in the receptor tyrosine kinase KIT. C-KIT or CD 117Approximately 8 of GISTs have mutations that activate a closely related receptor tyrosine kinase, platelet-derived growth factor receptor a PDGFRA.Some GISTs without mutated KIT or PDGFRA have mutations in other genes that function in these pathways NF1, BRAF, HRAS, or NRAS.Ref: Robbins Pathology; 9th edition; Page no: 775 