RESUMO
BACKGROUND AND AIMS: In an era of precision medicine, customized genotyping of GI stromal tumors by screening for driver mutations will become the standard of care. The fidelity of genotype concordance between paired cytology smears and surgical pathology specimens is unknown. In patients with either primary or metastatic sporadic disease, we sought to determine the frequency of KIT and PDGFRA pathogenic alterations within such specimens, imatinib sensitivity, and the concordance of pathogenic alterations between paired specimens. METHODS: DNA obtained from cytology smears from 36 patients, 24 of whom had paired surgical pathology specimens, underwent targeted next-generation sequencing by using a custom panel to evaluate somatic mutations within KIT (exon 2, 9, 10, 11, 13, 14, 15, 17, 18) and PDGFRA (exon 12, 14, 15, 18) genes. Patients with KIT and PDGRFA wild-type genes completed the Qiagen Human Comprehensive Cancer GeneRead DNAseq Targeted Array V2. RESULTS: Genotyping revealed KIT and PDGFRA mutations in 68% and 15% of patients. The wild-type population did not harbor mutations in BRAF, RAS family, SDHB, SETD2, or NF1. Imatinib sensitivity based on the oncogenic kinase mutation prevalence was estimated to be 68%. Mutational concordance between paired cytology and surgical pathology specimens was 96%. CONCLUSIONS: Our data have demonstrated the ability to stratify either primary or metastatic gastrointestinal stromal tumors by mutational subtype using a targeted next-generation sequencing 2 gene mutation panel. We highlight the ability to use cytology specimens obtained via minimally invasive techniques as a surrogate to surgical specimens given the high mutational landscape concordance between paired specimens.
Assuntos
DNA de Neoplasias/análise , Neoplasias Gastrointestinais/genética , Tumores do Estroma Gastrointestinal/genética , Técnicas de Genotipagem , Proteínas Proto-Oncogênicas c-kit/genética , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/genética , Antineoplásicos/uso terapêutico , Quimioterapia Adjuvante , Análise Citogenética , Resistencia a Medicamentos Antineoplásicos/genética , Aspiração por Agulha Fina Guiada por Ultrassom Endoscópico , Neoplasias Gastrointestinais/patologia , Neoplasias Gastrointestinais/terapia , Tumores do Estroma Gastrointestinal/patologia , Tumores do Estroma Gastrointestinal/terapia , Sequenciamento de Nucleotídeos em Larga Escala , Histona-Lisina N-Metiltransferase/genética , Humanos , Mesilato de Imatinib/uso terapêutico , Neurofibromina 1/genética , Medicina de Precisão , Proteínas Proto-Oncogênicas B-raf/genética , Radiologia Intervencionista , Succinato Desidrogenase/genética , Tomografia Computadorizada por Raios X , Proteínas ras/genéticaRESUMO
OBJECTIVES: In an era of precision medicine, our aim was to determine the frequency and theranostic potential of mutations identified in malignant lymph nodes (LNs) sampled by endoscopic ultrasound fine-needle aspiration (EUS FNA) of patients with rectal cancer by targeted next-generation sequencing (NGS). METHODS: The NGS Ion AmpliSeq Cancer Hotspot Panel v2 (Life Technologies, Carlsbad, CA) and MiSeq (Illumina, San Diego, CA) sequencers were used to sequence and assess for 2,800 or more possible mutations in 50 established cancer-associated genes. RESULTS: Among 102 patients, 89% had 194 pathogenic alterations identified in 19 genes. The identification of KRAS, NRAS, or BRAF mutations suggests that 42% are likely nonresponders to anti-epidermal growth factor receptor therapy. Among KRAS, NRAS, or BRAF wild-type patients, alterations in eight genes linked to alternative therapies were identified in 44%. CONCLUSIONS: Our data demonstrate the successful ability to apply a single multiplex test to allow multigene mutation detection from malignant LN cytology specimen DNA collected by EUS FNA.