TY - GEN N2 - The majority of gastrointestinal stromal tumor (GIST) are driven by mutations in KIT or platelet derived growth factor receptor alpha (PDGFRA) receptor tyrosine kinases. Imatinib, a type II KIT/PDGFRA tyrosine kinase inhibitor (TKI), is the first-line treatment for advanced GIST. However, the most common PDGFRA mutation, exon 18 D842V, is strongly resistant to imatinib and other type II TKIs. Over 80% of unique PDGFRA mutations in GIST occur in exon 18, and they include many complexities such as in/dels and additional point mutations. It is largely unknown how these mutations respond to imatinib, but many are assumed to be resistant, like D842V. Contrary to these assumptions, we have shown in our in vitro models that some of these clinically observed exon 18 mutations were imatinib sensitive. Imatinib sensitivity also seemed to be dependent on the characteristics of the amino acid at the 842 position, which led us to hypothesize that sensitivity is largely determined by this residue. To test this hypothesis, we cloned and expressed every possible variant at the 842 position in Ba/F3 cells and determined imatinib sensitivity via immunoblotting. DO - 10.6083/xk81jm14w DO - DOI AB - The majority of gastrointestinal stromal tumor (GIST) are driven by mutations in KIT or platelet derived growth factor receptor alpha (PDGFRA) receptor tyrosine kinases. Imatinib, a type II KIT/PDGFRA tyrosine kinase inhibitor (TKI), is the first-line treatment for advanced GIST. However, the most common PDGFRA mutation, exon 18 D842V, is strongly resistant to imatinib and other type II TKIs. Over 80% of unique PDGFRA mutations in GIST occur in exon 18, and they include many complexities such as in/dels and additional point mutations. It is largely unknown how these mutations respond to imatinib, but many are assumed to be resistant, like D842V. Contrary to these assumptions, we have shown in our in vitro models that some of these clinically observed exon 18 mutations were imatinib sensitive. Imatinib sensitivity also seemed to be dependent on the characteristics of the amino acid at the 842 position, which led us to hypothesize that sensitivity is largely determined by this residue. To test this hypothesis, we cloned and expressed every possible variant at the 842 position in Ba/F3 cells and determined imatinib sensitivity via immunoblotting. AD - Oregon Health and Science University AD - Oregon Health and Science University T1 - Predicting Imatinib responses in exon 18 PDGFRA-mutant GIST DA - 2022 AU - Khosroyani, Homma M. AU - Heinrich, Michael C. L1 - https://digitalcollections.ohsu.edu/record/9554/files/Khosroyani-Homma-OHSU-ResearchWeek-2022.pdf PB - Oregon Health and Science University PY - 2022 ID - 9554 L4 - https://digitalcollections.ohsu.edu/record/9554/files/Khosroyani-Homma-OHSU-ResearchWeek-2022.pdf KW - Sarcoma KW - Drug Resistance KW - Neoplasms KW - Tyrosine Protein Kinase Inhibitors KW - Gastrointestinal Stromal Tumors KW - Imatinib Mesylate KW - cancer KW - GIST TI - Predicting Imatinib responses in exon 18 PDGFRA-mutant GIST Y1 - 2022 L2 - https://digitalcollections.ohsu.edu/record/9554/files/Khosroyani-Homma-OHSU-ResearchWeek-2022.pdf LK - https://digitalcollections.ohsu.edu/record/9554/files/Khosroyani-Homma-OHSU-ResearchWeek-2022.pdf UR - https://digitalcollections.ohsu.edu/record/9554/files/Khosroyani-Homma-OHSU-ResearchWeek-2022.pdf ER -