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Media type:
E-Article
Title:
Elucidation of Additional Mutations By Next-Generation Sequencing Is of Clinical Significance in Patients with Rare MPNs and MDS/MPN Overlap Syndromes
Contributor:
Kirschner, Martin MJ;
Schemionek, Mirle;
Begemann, Matthias;
Isfort, Susanne;
Feldberg, Kristina;
Brümmendorf, Tim H.;
Koschmieder, Steffen
Description:
<jats:title>Abstract</jats:title>
<jats:p>Introduction:</jats:p>
<jats:p>Recently, next-generation sequencing (NGS) has revolutionized the molecular characterization and understanding of several hematologic entities, including myeloproliferative neoplasms (MPN) and myelodysplastic syndrome (MDS)/MPN overlap syndromes. Nevertheless, the frequency and clinical impact of the mutations detected by NGS, remain largely unclear, especially in rare MPN which were analyzed in this study.</jats:p>
<jats:p>Methods:</jats:p>
<jats:p>Thus, we established a novel amplicon-based NGS panel, comprising genes that are known to be recurrently mutated in MPN and/or MDS/MPN. Hot spot regions or all exons of the following 32 genes were chosen: ABL, ASXL1, BARD, CALR, CBL, CEBPA, CHEK2, CSF3R, DNMT3A, ETNK1, ETV6, EZH2, IDH1, IDH2, JAK2, KIT, KRAS, MPL, NFE2, NRAS, PDGFRA, PTPN11, RUNX1, SETBP1, SF3A1, SF3B1, SH3B2 (LNK), SRSF2, TCF12, TET2, TP53, U2AF1. After establishing this panel, peripheral blood samples of 19 patients, which were diagnosed with CMML(10), aCML(2), MPNu(1), MDS/MPNu or other MPN(6), were analyzed on a MiSeq® illumina sequencer. Variants were only analyzed if the absolute coverage at each SNV site was >50 reads, and the absolute coverage of the mutant allele was 10 or more reads and its relative coverage exceeded 10%.</jats:p>
<jats:p>Results:</jats:p>
<jats:p>Mean coverage of the run was 1516 reads with good Phred-score quality parameters (>84% of called bases with Q-score >= 30). In 300 bidirectional cycles, a yield of nearly seven gigabases of sequencing data was reached. One out of 19 analyzed patients was excluded from analysis due to insufficient DNA quality. In 89% of the samples(16/18), mutations were detected which had not previously been known to be present in these patients. TET2 (50%, 9/18) and SETBP1 mutations were the most common (44%, 8/18). As expected, TET2 mutations were spread over the entire gene and SETBP1 mutations were restricted to the known hot spot region (exon 4, c.2602-c.2620). Additionally, CSF3R mutations were detected in 22% (4/18) of patients. Epigenetic regulator genes were also affected as EZH2 mutations were detected in 17% (3/18), ASXL1 mutations in 39% (7/18) and IDH1/2 mutations were found in 6% (1/18) of all samples, whereas DNMT3A mutations were not present. Further mutations were found in the following genes: CBL (11%), ETV6 (6%), JAK2V617F (6%), KRAS (11%), NRAS (11%), PTPN11 (6%), SH2B3 (6%) and SRSF2 (11%). Besides previously known mutations, several novel variants could be detected. All but one patient harbored more than one of these mutations.</jats:p>
<jats:p>Furthermore, clinical correlates and morphologic and cytogenetic subtypes of each patient were available to associate with the NGS data of individual patients. For example, the one patient with a solitary NRAS c.35G>A (amino acid: p.G12D) mutation showed the most aggressive clinical course in our cohort with transformation to AML only 7 months after first diagnosis of CMML. Moreover, CSF3R mutations have been shown to confer sensitivity to ruxolitinib and may thus open up new avenues of treatment for our patients.</jats:p>
<jats:p>Conclusion:</jats:p>
<jats:p>In a cohort of unclassified MPN and rare MDS/MPN subtypes, NGS is a powerful tool to characterize samples more extensively. Our data suggests that a more comprehensive understanding of the mutational spectrum may have important clinical impact in individual patients, including diagnosis, prognosis, and more specific treatment.</jats:p>
<jats:sec>
<jats:title>Disclosures</jats:title>
<jats:p>Isfort: Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel; BMS: Honoraria; Mundipharma: Other: Travel; Amgen: Other: Travel; Hexal: Other: Travel. Brümmendorf:Novartis: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Ariad: Consultancy, Honoraria; Patent on the use of imatinib and hypusination inhibitors: Patents & Royalties. Koschmieder:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.</jats:p>
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