c-KIT mutation analysis
KIT is mutated in ~85% of GIST (Heinrich et al. 2003). The vast majority of KIT mutations are found in exon 11 (juxtamembrane domain; ~70%), exon 9 (extracellular dimerization motif; 10–15%), exon 13 (tyrosine kinase 1 (TK1) domain; 1–3%), and exon 17 (tyrosine kinase 2 [TK2] domain and activation loop; 1–3%) (Heinrich et al. 2003). Secondary KIT mutations in exons 13, 14, 17, and 18 are commonly identified in post-imatinib biopsy specimens, after patients have developed acquired resistance.
Heinrich MC, Corless CL, Demetri GD, Blanke CD, von Mehren M, Joensuu H, McGreevey LS, Chen CJ, Van den Abbeele AD, Druker BJ, Kiese B, Eisenberg B, Roberts PJ, Singer S, Fletcher CD, Silberman S, Dimitrijevic S, Fletcher JA. Kinase mutations and imatinib response in patients with metastatic gastrointestinal stromal tumor. J Clin Oncol. 2003 Dec 1;21(23):4342-9.