Genetic Characterization of Molecular Targets in Korean Patients with Gastrointestinal Stromal Tumors

PURPOSE: Gastrointestinal stromal tumors (GISTs) frequently harbor activating gene mutations in either KIT or platelet-derived growth factor receptor A (PDGFRA) and are highly responsive to several selective tyrosine kinase inhibitors. In this study, a targeted next-generation sequencing (NGS) assay with an Oncomine Focus Assay (OFA) panel was used for the genetic characterization of molecular targets in 30 Korean patients with GIST.MATERIALS AND METHODS: Using the OFA that enables rapid and simultaneous detection of hotspots, single nucleotide variants (SNVs), insertion and deletions (Indels), copy number variants (CNVs), and gene fusions across 52 genes relevant to solid tumors, targeted NGS was performed using genomic DNA extracted from formalin-fixed and paraffin-embedded samples of 30 GISTs.RESULTS: Forty-three hotspot/other likely pathogenic variants (33 SNVs, 8 Indels, and 2 amplifications) in 16 genes were identified in 26 of the 30 GISTs. KIT variants were most frequent (44%, 19/43), followed by 6 variants in PIK3CA, 3 in PDGFRA, 2 each in JAK1 and EGFR, and 1 each in AKT1, ALK, CCND1, CTNNB1, FGFR3, FGFR4, GNA11, GNAQ, JAK3, MET, and SMO. Based on the mutation types, majority of the variants carried missense mutations (60%, 26/43), followed by 8 frameshifts, 6 nonsense, 1 stop-loss, and 2 amplifications.CONCLUSIONS: Our study confirmed the advantage of using targeted NGS with a cancer gene panel to efficiently identify mutations associated with GISTs. These findings may provide a molecular genetic basis for developing new drugs targeting these gene mutations for GIST therapy.

Progress in molecular targeting therapy for gastrointestinal stromal tumors / 中国肿瘤生物治疗杂志

@#Gastrointestinal stromal tumors (GISTs) are the most common malignant tumor of abdominal soft tissue. It originates from Cahal (Cajal) interstitial cells or common precursor cells, and is driven by the mutated KIT gene or platelet-derived growth factor receptor alpha (PDGFRa) gene, all expressing type Ⅲ tyrosine kinase receptors. Imatinib mesylate, a tyrosine kinase receptor inhibitor, has been used for the standard treatment of advanced GIST, which has achieved remarkable results. Thus, GIST has become the most successful example of target therapy for solid tumors. In the context of the era of precision medicine, with the deepening in research of GISTs molecular biology，the molecular targeted treatment of GISTs has obtained a clear venation from the first-line, second-line and third-line of the advanced stage to the postoperative auxiliary and preoperative treatment, providing significant survival benefits for GISTs patients. This article systematically and comprehensively combed the preoperative and postoperative molecular targeting therapy from advanced GIST to early GIST, and analyzed the problems, proposed solutions and prospects for the future, aiming to provide reference for clinical application of molecular targeting drug therapy for GIST.

Detection of KIT gene of a case with serious phenotypes of piebaldism / 中山大学学报(医学科学版)

[Objective]To investigate the mutations of KIT gene and SLUG(SNAI2)gene in one patients with piebaldism in Chi?na.[Methods]All coding exons and exon-intron boundaries of KIT gene and SLUG gene were amplified by PCR. The PCR products were sequenced. The DNA samples from 50 normal subjects were also sequenced for control.[Results]The novel mutation,c.860T>A (p.V287E),was detected in patient. This mutation was absent in his parents and the controls ,indicating a de novo mutation. The de?tection result of all coding exons and exon-intron boundaries of SLUG gene was normal.This p.V287E mutation was located in the ex?tracellular ligand-bindingdomain(ectodomain)of KIT,which may generate clash with E249 and disrupt the conformation ofβD andβD/βE of D3 that required for SCF(stem cell factor)binding.[Conclusion]We have identified a novel mutation of KIT gene,c.860T>A(p.V287E),which is probably associated with serious phenotypes of piebaldism.

Mastocitosis local, sistémica y alergia medicamentosa / Local and systemic mastocytosis anddrug allergy

Se exponen datos relacionados con la histología, fisiología y patología de los mastocitos, tanto normales como patológicos, y el papel de la alergia medicamentosa en la mastocitosis, así como las repercusiones psicopatológicas de la enfermedad y las bases neuroquímicas de dichos trastornos.

Data concerning the biological aspects of mastocytes, its pathology and the importance of childhood and adult mastocytosis are described. The role of drug allergy in mastocytosis is discussed. The psychopathological and neurochemical aspects of these conditions are exposed.

Diffuse cutaneous mastocytosis: a case report and mutation analysis of the KIT gene / 中华皮肤科杂志

Objective To analyze KIT gene mutations in one patient with diffuse cutaneous mastocytosis (DCM),and to provide a basis for the prediction of prognosis and selection of treatment.Methods Clinical data were collected from a boy with DCM.Peripheral blood samples were obtained from the patient,his parents and 200 unrelated healthy human controls.PCR was performed to amplify 21 coding exons and their flanking sequences of the KIT gene followed by DNA sequencing.Results A heterozygous missense mutation (c.1526A ＞ T),which leads to the mutation p.Lys509Ile,was detected in the KIT gene of the patient,but not in his parents or the healthy controls.Conclusion The heterozygous missense mutation p.Lys509Ile in the KIT gene may be a cause of DCM.

Testes bioquímico (albumina e proteína de ligação da vitamina D) e molecular (gene KIT) para detecção de marcadores genéticos para pelagem tobiana em cavalos pampa e paint / Biochemical (albumin and vitamin D-binding protein) and molecular (KIT gene) tests for detection of genetic markers for tobiano coat color in pampa and paint horses

Foram utilizados 159 cavalos Pampa, registrados na Associação Brasileira dos Criadores de Cavalo Pampa, e um grupo-controle, de 32 cavalos da raça Paint, ambos os grupos provenientes de plantéis de diferentes regiões brasileiras, com o objetivo de comparar os testes bioquímico e molecular para detecção de marcadores genéticos para pelagem tobiana em cavalos Pampa. Houve diferença significativa (P<0,001) entre os testes bioquímico e molecular, nos cavalos Pampa, mas o mesmo fato não ocorreu com os da raça Paint. Os resultados mostraram que o marcador molecular (KIT) foi mais eficiente na identificação dos prováveis cavalos homozigotos do que os marcadores bioquímicos albumina (Al) e proteína de ligação da vitamina D (Gc), em ambas as raças.

In this study, 159 Pampa horses, registered at the Associação Brasileira dos Criadores de Cavalo Pampa, and a control group of 32 Paint horses, both coming from herds located in different Brazilian regions, were used to compare biochemical and molecular tests for detection of genetic markers for the Tobiano coat color pattern in Pampa horses. Difference (P<0.001) between biochemical and molecular tess in Pampa horses was observed, but not for the Paint horses. The results showed that the molecular marker (KIT) was more efficient to identify the probable homozygous dominant horses than the biochemical markers albumin (Al) and vitamin D-binding Protein (Gc), in both breeds.

The genetic and immunohistochemical characteristics in imatinib-resistant gastrointestinal stromal tumor / 肿瘤

Objective: The application of the tyrosine kinase inhibitor imatinib changed the treatment style and the prognosis foreground of gastrointestinal stromal tumor (GIST). The prognosis of advanced GIST was improved significantly. However, the number of patients with imatinib resistance increased continuously with enlongation of treatment period. Imatinib resistance became a hot point recently. This study aimed to explore the mechanism responsible for the acquired resistance to imatinib. Methods: With the bidirectional DNA sequencing and the analysis of an ABI PRISM 310 capillary electrophoresis system, this work sequenced the extrons 9, 11, 13, and 17 of KIT gene and the extron 12 and 18 in platelet derived growth factor receptor (PDGFR) α gene in the 9 GIST patients who were resistant to imatinib or obtained stable disease (SD) during imatinib treatment. Results: Activating mutations of KIT gene existed in 7 of 9 cases of GIST patients. Six cases had the KIT gene mutation in exon 11 encoding the juxtamembrane domain and 1 case had mutation in exon 13. Secondary KIT mutations were identified in the 4 imatinib-resistant patients. This work found an identical novel missense mutation in exon 17, T2467T-→T2467G, which caused a substitution of Tyr by Asp at codon 823 (Y823 D) in tyrosine kinase domain of KIT. Conclusion: The imatinib resistance may be related with missense mutation in exon 17, T2467T→T2467G, in tyrosine kinase domain of KIT.