Durable response with a combination of imatinib and sorafenib in KIT exon 17 mutant gastrointestinal stromal tumor

Latest Advances in the Management of Pediatric Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumor is the most common mesenchymal neoplasm of the gastrointestinal tract, usually found in elderly adults. It is infrequent among pediatric patients and usually differs biologically from adult-type diseases presenting mutations of KIT and PDGFR genes. In this population, more frequent is the wild-type GIST possessing SDH, TRK, RAS, NF1 mutations, among others. Both tumor types require individualized treatment with kinase inhibitors that are still being tested in the pediatric population due to the different neoplasm biology. We review the latest updates to the management of pediatric gastrointestinal tumors with a particular focus on the advances in molecular biology of the disease that enables the definition of possible resistance. Emerging treatment with kinase inhibitors that could serve as targeted therapy is discussed, especially with multikinase inhibitors of higher generation, the effectiveness of which has already been confirmed in the adult population.

Rational Drug Design Approach of Receptor Tyrosine Kinase Type III Inhibitors

Rational drug design is accomplished through the complementary use of structural biology and computational biology of biological macromolecules involved in disease pathology. Most of the known theoretical approaches for drug design are based on knowledge of the biological targets to which the drug binds. This approach can be used to design drug molecules that restore the balance of the signaling pathway by inhibiting or stimulating biological targets by molecular modeling procedures as well as by molecular dynamics simulations. Type III receptor tyrosine kinase affects most of the fundamental cellular processes including cell cycle, cell migration, cell metabolism, and survival, as well as cell proliferation and differentiation. Many inhibitors of successful rational drug design show that some computational techniques can be combined to achieve synergistic effects.

Targeting gastrointestinal stromal tumors: the role of regorafenib

Gastrointestinal stromal tumor (GIST) is a devastating disease in the metastatic setting, but its natural history has been dramatically altered by the development of small molecule tyrosine kinase inhibitors, most notably imatinib. Although patients with advanced GIST live much longer today than they did in the past, imatinib-refractory disease remains a tremendous problem. For disease that is refractory to imatinib and sunitinib, regorafenib is an excellent option. In this review, we discuss the biology and clinical work establishing regorafenib as the standard of care for advanced GIST refractory to both imatinib and sunitinib.

Inactivity of imatinib in gastrointestinal stromal tumors (GISTs) harboring a KIT activation-loop domain mutation (exon 17 mutation pN822K)

The development of gastrointestinal stromal tumors (GISTs) is largely driven by mutations in the KIT and PDGFRα genes. Imatinib mesylate is an oral small molecular tyrosine kinase inhibitor that mainly targets abl, c-KIT, and PDGFRα. Imatinib achieves disease control in approximately 70%–85% of patients with advanced GIST, and the median progression-free survival is 20–24 months. The efficacy of imatinib correlates with tumor kinase mutational status (exon 11 mutations mainly), and some mutations are known to be responsible for primary and secondary imatinib resistance. Beyond these, there are many other mutations that are considered rare and are associated with unknown clinical behavior. In the literature, there are poor and inconsistent data about the inhibitor sensitivity of mutations occurring in the activation-loop domain encoded by exon 17. In this article, we focus on a case of a patient suffering from GIST, harboring an extremely rare KIT activation-loop domain mutation (exon 17 mutation pN822K) treated with imatinib. A review of the literature is also presented.

Advances in research of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, arising from the interstitial cells of Cajal (ICCs), primarily in the stomach and small intestine. The growth of most GISTs is driven by the mutations of genes encoding oncogenic receptor tyrosine kinase KIT or platelet derived growth factor receptor alpha (PDGFRα). The pathogenesis of GISTs may involve ICCs, microRNAs (miRNAs), signaling pathways, DNA methylation, and KIT or PDGFRα gene mutations. This article systematically describes the advances in research of GISTs in terms of clinical features, imaging characteristics, endoscopic features, histopathological features, diagnosis and therapies.