KIT V654A

We found that farnesyltransferase inhibitors tipifarnib and lonafarnib, which inhibit RAS activity, inhibited ERK activation mediated by both wild-type and KIT mutants, which often occur in gastrointestinal stromal tumors. Similar to the primary KIT mutations, secondary mutations of KIT-induced ERK activation and cell response were inhibited by both inhibitors. Our results suggested the potential benefit of farnesyltransferase inhibitors either alone or combined with imatinib in the treatment of gastrointestinal stromal tumors carrying KIT mutations.

P3; CtDNA sequencing efficiently detects KIT/PDGFRA mutations and prognosticates outcomes in patients with TKI-resistant GIST treated with avapritinib. ctDNA analysis can be used to monitor disease progression and provide more personalized treatment.

Anlotinib showed moderate antitumor activity in drug-resistant GIST cell lines in vitro, and good PFS and better tolerance in second-line therapy study.

The best outcome was achieved using imatinib in a patient with a KIT mutation (p.W557R)...The patient was still on ponatinib when the observation period ended. We demonstrate that comprehensive molecular analysis provides clinically relevant information in a subgroup of TET patients... We demonstrate that comprehensive molecular analysis provides clinically relevant information in a subgroup of TET patients. Thymoma, TCs, and NETs present with different molecular characteristics. Distinction between immunologically hot and cold TCs may have value for risk stratification and therapeutic strategies.

The most highly enriched individual driver mutations in metastatic tumors were mutations known to drive resistance to hormone therapies in breast and prostate cancer (ESR1 and AR), anti-EGFR therapy in non-small cell lung cancer (EGFR T790M), and imatinib in gastrointestinal cancer (KIT V654A)...Overall, this implies that initial acquisition of driver mutations is predominantly shaped by the tissue of origin, where specific mutations define the developing primary tumor and drive growth, immune escape, and tolerance to chromosomal instability. However, acquisition of driver mutations that contribute to metastatic disease is less specific, with the main genomic drivers of metastatic cancer evolution associating with resistance to therapy.

Background: The genotype of primary mutations predicts imatinib response in untreated metastatic GIST...Regorafenib showed similar activity regardless of KIT mutational status and the location of KIT mutation... Hybrid capture-based plasma sequencing detects ctDNA in the majority of patients with advanced TKI-resistant GIST, including heterogeneity of KIT mutations. This study is the first to show that ctDNA sequencing correlates with outcomes in pretreated GIST. Identification of ABP (exon13/14) KIT mutations negatively correlates with avapritinib activity.

Ponatinib demonstrated activity in advanced GIST, particularly in KIT ex11-positive disease. ctDNA analysis confirmed heterogeneous resistance mutations in TKI-pretreated advanced GIST. Safety was consistent with previous studies.