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  • The American Association for Cancer Research (AACR)  (4)
  • International Union of Crystallography (IUCr)  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 576-578 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2018-09-15
    Description: Purpose: Plasma cell-free DNA (cfDNA) genotyping is increasingly used in cancer care, but assay accuracy has been debated. Because most cfDNA is derived from peripheral blood cells (PBC), we hypothesized that nonmalignant mutations harbored by hematopoietic cells (clonal hematopoiesis, CH) could be a cause of false-positive plasma genotyping. Experimental Design: We identified patients with advanced non–small cell lung cancer (NSCLC) with KRAS, JAK2 , or TP53 mutations identified in cfDNA. With consent, PBC DNA was tested using droplet digital PCR (ddPCR) or next-generation sequencing (NGS) to test for CH-derived mutations. Results: We first studied plasma ddPCR results from 58 patients with EGFR -mutant NSCLC. Two had KRAS G12X detected in cfDNA, and both were present in PBC, including one where the KRAS mutation was detected serially for 20 months. We then studied 143 plasma NGS results from 122 patients with NSCLC and identified 5 JAK2 V617F mutations derived from PBC. In addition, 108 TP53 mutations were detected in cfDNA; for 33 of the TP53 mutations, PBC and tumor NGS were available for comparison, and 5 were present in PBC but absent in tumor, consistent with CH. Conclusions: We find that most JAK2 mutations, some TP53 mutations, and rare KRAS mutations detected in cfDNA are derived from CH not tumor. Clinicians ordering plasma genotyping must be prepared for the possibility that mutations detected in plasma, particularly in genes mutated in CH, may not represent true tumor genotype. Efforts to use plasma genotyping for cancer detection may need paired PBC genotyping so that CH-derived mutations are not misdiagnosed as occult malignancy. Clin Cancer Res; 24(18); 4437–43. ©2018 AACR . See related commentary by Bauml and Levy, p. 4352
    Print ISSN: 1078-0432
    Electronic ISSN: 1557-3265
    Topics: Medicine
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  • 3
    Publication Date: 2018-10-02
    Description: Purpose: Despite the challenge to directly target mutant KRAS due to its high GTP affinity, some agents are under development against downstream signaling pathways, such as MEK inhibitors. However, it remains controversial whether MEK inhibitors can boost current chemotherapy in KRAS -mutant lung tumors in clinic. Considering the genomic heterogeneity among patients with lung cancer, it is valuable to test potential therapeutics in KRAS mutation–driven mouse models. Experimental Design: We first compared the pERK1/2 level in lung cancer samples with different KRAS substitutions and generated a new genetically engineered mouse model whose tumor was driven by KRAS G12C , the most common KRAS mutation in lung cancer. Next, we evaluated the efficacy of selumetinib or its combination with chemotherapy, in KRAS G12C tumors compared with KRAS G12D tumors. Moreover, we generated KRAS G12C /p53 R270H model to explore the role of a dominant negative p53 mutation detected in patients in responsiveness to MEK inhibition. Results: We determined higher pERK1/2 in KRAS G12C lung tumors compared with KRAS G12D . Using mouse models, we further identified that KRAS G12C tumors are significantly more sensitive to selumetinib compared with Kras G12D tumors. MEK inhibition significantly increased chemotherapeutic efficacy and progression-free survival of KRAS G12C mice. Interestingly, p53 co-mutation rendered KRAS G12C lung tumors less sensitive to combination treatment with selumetinib and chemotherapy. Conclusions: Our data demonstrate that unique KRAS mutations and concurrent mutations in tumor-suppressor genes are important factors for lung tumor responses to MEK inhibitor. Our preclinical study supports further clinical evaluation of combined MEK inhibition and chemotherapy for lung cancer patients harboring KRAS G12C and wild-type p53 status. Clin Cancer Res; 24(19); 4854–64. ©2018 AACR .
    Print ISSN: 1078-0432
    Electronic ISSN: 1557-3265
    Topics: Medicine
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  • 4
    Publication Date: 2018-10-16
    Description: Purpose: Inflammatory bowel disease–associated colorectal cancers (IBD-CRC) are associated with a higher mortality than sporadic colorectal cancers. The poorly defined molecular pathogenesis of IBD-CRCs limits development of effective prevention, detection, and treatment strategies. We aimed to identify biomarkers using whole-exome sequencing of IBD-CRCs to guide individualized management. Experimental Design: Whole-exome sequencing was performed on 34 formalin-fixed paraffin-embedded primary IBD-CRCs and 31 matched normal lymph nodes. Computational methods were used to identify somatic point mutations, small insertions and deletions, mutational signatures, and somatic copy number alterations. Mismatch repair status was examined. Results: Hypermutation was observed in 27% of IBD-CRCs. All hypermutated cancers were from the proximal colon; all but one of the cancers with hypermutation had defective mismatch repair or somatic mutations in the proofreading domain of DNA POLE . Hypermutated IBD-CRCs had increased numbers of predicted neo-epitopes, which could be exploited using immunotherapy. We identified six distinct mutation signatures in IBD-CRCs, three of which corresponded to known mechanisms of mutagenesis. Driver genes were also identified. Conclusions: IBD-CRCs should be evaluated for hypermutation and defective mismatch repair to identify patients with a higher neo-epitope load who may benefit from immunotherapies. Prospective trials are required to determine whether IHC to detect loss of MLH1 expression in dysplastic colonic tissue could identify patients at increased risk of developing IBD-CRC. We identified mutations in genes in IBD-CRCs with hypermutation that might be targeted therapeutically. These approaches would complement and individualize surveillance and treatment programs. Clin Cancer Res; 24(20); 5133–42. ©2018 AACR .
    Print ISSN: 1078-0432
    Electronic ISSN: 1557-3265
    Topics: Medicine
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  • 5
    Publication Date: 2018-06-02
    Description: Purpose: HER2 (or ERBB2 ) aberrations, including both amplification and mutations, have been classified as oncogenic drivers that contribute to 2% to 6% of lung adenocarcinomas. HER2 amplification is also an important mechanism for acquired resistance to EGFR tyrosine kinase inhibitors (TKI). However, due to limited preclinical studies and clinical trials, currently there is still no available standard of care for lung cancer patients with HER2 aberrations. To fulfill the clinical need for targeting HER2 in patients with non–small cell lung cancer (NSCLC), we performed a comprehensive preclinical study to evaluate the efficacy of a third-generation TKI, osimertinib (AZD9291). Experimental Design: Three genetically modified mouse models (GEMM) mimicking individual HER2 alterations in NSCLC were generated, and osimertinib was tested for its efficacy against these HER2 aberrations in vivo . Results: Osimertinib treatment showed robust efficacy in HER2 wt overexpression and EGFR del19/HER2 models, but not in HER2 exon 20 insertion tumors. Interestingly, we further identified that combined treatment with osimertinib and the BET inhibitor JQ1 significantly increased the response rate in HER2 -mutant NSCLC, whereas JQ1 single treatment did not show efficacy. Conclusions: Overall, our data indicated robust antitumor efficacy of osimertinib against multiple HER2 aberrations in lung cancer, either as a single agent or in combination with JQ1. Our study provides a strong rationale for future clinical trials using osimertinib either alone or in combination with epigenetic drugs to target aberrant HER2 in patients with NSCLC. Clin Cancer Res; 24(11); 2594–604. ©2018 AACR . See related commentary by Cappuzzo and Landi, p. 2470
    Print ISSN: 1078-0432
    Electronic ISSN: 1557-3265
    Topics: Medicine
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