Publications by authors named "Sharon Heath"

29 Publications

  • Page 1 of 1

Genome Sequencing as an Alternative to Cytogenetic Analysis in Myeloid Cancers.

N Engl J Med 2021 03;384(10):924-935

From the Department of Pathology and Immunology (E.J.D., M.C.S., A.E.O.H., J.N., J.E.P., D.H.S.), McDonnell Genome Institute (M.O., R.W., S.M., A.B., S.K., J.G., F.D., R.S.F., D.H.S.), and the Divisions of Oncology (J.R., E.H., S.E.H., M.J.C., M.A.J., G.L.U., C.A.M., D.C.L., M.J.W., P.W., J.F.D., T.J.L., D.H.S.) and Biostatistics (J.D.B.), Department of Medicine, Washington University School of Medicine, St. Louis.

Background: Genomic analysis is essential for risk stratification in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS). Whole-genome sequencing is a potential replacement for conventional cytogenetic and sequencing approaches, but its accuracy, feasibility, and clinical utility have not been demonstrated.

Methods: We used a streamlined whole-genome sequencing approach to obtain genomic profiles for 263 patients with myeloid cancers, including 235 patients who had undergone successful cytogenetic analysis. We adapted sample preparation, sequencing, and analysis to detect mutations for risk stratification using existing European Leukemia Network (ELN) guidelines and to minimize turnaround time. We analyzed the performance of whole-genome sequencing by comparing our results with findings from cytogenetic analysis and targeted sequencing.

Results: Whole-genome sequencing detected all 40 recurrent translocations and 91 copy-number alterations that had been identified by cytogenetic analysis. In addition, we identified new clinically reportable genomic events in 40 of 235 patients (17.0%). Prospective sequencing of samples obtained from 117 consecutive patients was performed in a median of 5 days and provided new genetic information in 29 patients (24.8%), which changed the risk category for 19 patients (16.2%). Standard AML risk groups, as defined by sequencing results instead of cytogenetic analysis, correlated with clinical outcomes. Whole-genome sequencing was also used to stratify patients who had inconclusive results by cytogenetic analysis into risk groups in which clinical outcomes were measurably different.

Conclusions: In our study, we found that whole-genome sequencing provided rapid and accurate genomic profiling in patients with AML or MDS. Such sequencing also provided a greater diagnostic yield than conventional cytogenetic analysis and more efficient risk stratification on the basis of standard risk categories. (Funded by the Siteman Cancer Research Fund and others.).
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http://dx.doi.org/10.1056/NEJMoa2024534DOI Listing
March 2021

Immune Escape of Relapsed AML Cells after Allogeneic Transplantation.

N Engl J Med 2018 12 31;379(24):2330-2341. Epub 2018 Oct 31.

From the Division of Oncology, Department of Internal Medicine (M.J.C., A.A.P., M.P.R., C.A.M., E.C., N.M.H., L.D.W., J.S.W., S.E.H., D.C.L., M.J.W., P.W., T.J.L., J.F.D.), the McDonnell Genome Institute (A.A.P., C.A.M., M.O., C.C.F., R.S.F., L.D.W., T.J.L.), the Department of Pathology and Immunology (E.J.D., J.E.P.), and the Division of Biostatistics (J.D.B.), Washington University in St. Louis, St. Louis; the Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN (J.M.K.); the Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH (R.K.W.); and the Center for Cancer Research, Massachusetts General Hospital, Boston (T.A.G.).

Background: As consolidation therapy for acute myeloid leukemia (AML), allogeneic hematopoietic stem-cell transplantation provides a benefit in part by means of an immune-mediated graft-versus-leukemia effect. We hypothesized that the immune-mediated selective pressure imposed by allogeneic transplantation may cause distinct patterns of tumor evolution in relapsed disease.

Methods: We performed enhanced exome sequencing on paired samples obtained at initial presentation with AML and at relapse from 15 patients who had a relapse after hematopoietic stem-cell transplantation (with transplants from an HLA-matched sibling, HLA-matched unrelated donor, or HLA-mismatched unrelated donor) and from 20 patients who had a relapse after chemotherapy. We performed RNA sequencing and flow cytometry on a subgroup of these samples and on additional samples for validation.

Results: On exome sequencing, the spectrum of gained and lost mutations observed with relapse after transplantation was similar to the spectrum observed with relapse after chemotherapy. Specifically, relapse after transplantation was not associated with the acquisition of previously unknown AML-specific mutations or structural variations in immune-related genes. In contrast, RNA sequencing of samples obtained at relapse after transplantation revealed dysregulation of pathways involved in adaptive and innate immunity, including down-regulation of major histocompatibility complex (MHC) class II genes ( HLA-DPA1, HLA-DPB1, HLA-DQB1, and HLA-DRB1) to levels that were 3 to 12 times lower than the levels seen in paired samples obtained at presentation. Flow cytometry and immunohistochemical analysis confirmed decreased expression of MHC class II at relapse in 17 of 34 patients who had a relapse after transplantation. Evidence suggested that interferon-γ treatment could rapidly reverse this phenotype in AML blasts in vitro.

Conclusions: AML relapse after transplantation was not associated with the acquisition of relapse-specific mutations in immune-related genes. However, it was associated with dysregulation of pathways that may influence immune function, including down-regulation of MHC class II genes, which are involved in antigen presentation. These epigenetic changes may be reversible with appropriate therapy. (Funded by the National Cancer Institute and others.).
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http://dx.doi.org/10.1056/NEJMoa1808777DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6322675PMC
December 2018

Mutation Clearance after Transplantation for Myelodysplastic Syndrome.

N Engl J Med 2018 Sep;379(11):1028-1041

From the Department of Pathology and Immunology (E.J.D.), the Department of Medicine, Division of Oncology (M.A.J., C.A.M., N.E., J.S., K.E., J.R., S.E.H., K.B., L.D.W., M.J.C., I.P., J.S.W., G.L.U., D.C.L., J.F.D., P.W., T.J.L., M.J.W.), the McDonnell Genome Institute (G.S.C., C.A.M., H.A., R.S.F., C.C.F., M.O.), the Department of Medicine, Division of Hospital Medicine (R.S.), and Siteman Biostatistics Shared Resource, Siteman Cancer Center (K.T.), Washington University School of Medicine in St. Louis, St. Louis; and Massachusetts General Hospital Cancer Center, Boston (T.A.G.).

Background: Allogeneic hematopoietic stem-cell transplantation is the only curative treatment for patients with myelodysplastic syndrome (MDS). The molecular predictors of disease progression after transplantation are unclear.

Methods: We sequenced bone marrow and skin samples from 90 adults with MDS who underwent allogeneic hematopoietic stem-cell transplantation after a myeloablative or reduced-intensity conditioning regimen. We detected mutations before transplantation using enhanced exome sequencing, and we evaluated mutation clearance by using error-corrected sequencing to genotype mutations in bone marrow samples obtained 30 days after transplantation. In this exploratory study, we evaluated the association of a mutation detected after transplantation with disease progression and survival.

Results: Sequencing identified at least one validated somatic mutation before transplantation in 86 of 90 patients (96%); 32 of these patients (37%) had at least one mutation with a maximum variant allele frequency of at least 0.5% (equivalent to 1 heterozygous mutant cell in 100 cells) 30 days after transplantation. Patients with disease progression had mutations with a higher maximum variant allele frequency at 30 days than those who did not (median maximum variant allele frequency, 0.9% vs. 0%; P<0.001). The presence of at least one mutation with a variant allele frequency of at least 0.5% at day 30 was associated with a higher risk of progression (53.1% vs. 13.0%; conditioning regimen-adjusted hazard ratio, 3.86; 95% confidence interval [CI], 1.96 to 7.62; P<0.001) and a lower 1-year rate of progression-free survival than the absence of such a mutation (31.3% vs. 59.3%; conditioning regimen-adjusted hazard ratio for progression or death, 2.22; 95% CI, 1.32 to 3.73; P=0.005). The rate of progression-free survival was lower among patients who had received a reduced-intensity conditioning regimen and had at least one persistent mutation with a variant allele frequency of at least 0.5% at day 30 than among patients with other combinations of conditioning regimen and mutation status (P≤0.001). Multivariate analysis confirmed that patients who had a mutation with a variant allele frequency of at least 0.5% detected at day 30 had a higher risk of progression (hazard ratio, 4.48; 95% CI, 2.21 to 9.08; P<0.001) and a lower 1-year rate of progression-free survival than those who did not (hazard ratio for progression or death, 2.39; 95% CI, 1.40 to 4.09; P=0.002).

Conclusions: The risk of disease progression was higher among patients with MDS in whom persistent disease-associated mutations were detected in the bone marrow 30 days after transplantation than among those in whom these mutations were not detected. (Funded by the Leukemia and Lymphoma Society and others.).
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http://dx.doi.org/10.1056/NEJMoa1804714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6309244PMC
September 2018

Subclones dominate at MDS progression following allogeneic hematopoietic cell transplant.

JCI Insight 2018 03 8;3(5). Epub 2018 Mar 8.

Department of Medicine, Division of Oncology.

Allogeneic hematopoietic cell transplantation (alloHCT) is a potentially curative treatment for myelodysplastic syndromes (MDS), but patients who relapse after transplant have poor outcomes. In order to understand the contribution of tumor clonal evolution to disease progression,we applied exome and error-corrected targeted sequencing coupled with copy number analysis to comprehensively define changes in the clonal architecture of MDS in response to therapy using 51 serially acquired tumor samples from 9 patients who progressed after an alloHCT. We show that small subclones before alloHCT can drive progression after alloHCT. Notably, at least one subclone expanded or emerged at progression in all patients. Newly acquired structural variants (SVs) were present in an emergent/expanding subclone in 8 of 9 patients at progression, implicating the acquisition of SVs as important late subclonal progression events. In addition, pretransplant therapy with azacitidine likely influenced the mutation spectrum and evolution of emergent subclones after alloHCT. Although subclone evolution is common, founding clone mutations are always present at progression and could be detected in the bone marrow as early as 30 and/or 100 days after alloHCT in 6 of 8 (75%) patients, often prior to clinical progression. In conclusion, MDS progression after alloHCT is characterized by subclonal expansion and evolution, which can be influenced by pretransplant therapy.
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http://dx.doi.org/10.1172/jci.insight.98962DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5922277PMC
March 2018

Cellular stressors contribute to the expansion of hematopoietic clones of varying leukemic potential.

Nat Commun 2018 01 31;9(1):455. Epub 2018 Jan 31.

Division of Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA.

Hematopoietic clones harboring specific mutations may expand over time. However, it remains unclear how different cellular stressors influence this expansion. Here we characterize clonal hematopoiesis after two different cellular stressors: cytotoxic therapy and hematopoietic transplantation. Cytotoxic therapy results in the expansion of clones carrying mutations in DNA damage response genes, including TP53 and PPM1D. Analyses of sorted populations show that these clones are typically multilineage and myeloid-biased. Following autologous transplantation, most clones persist with stable chimerism. However, DNMT3A mutant clones often expand, while PPM1D mutant clones often decrease in size. To assess the leukemic potential of these expanded clones, we genotyped 134 t-AML/t-MDS samples. Mutations in non-TP53 DNA damage response genes are infrequent in t-AML/t-MDS despite several being commonly identified after cytotoxic therapy. These data suggest that different hematopoietic stressors promote the expansion of distinct long-lived clones, carrying specific mutations, whose leukemic potential depends partially on the mutations they harbor.
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http://dx.doi.org/10.1038/s41467-018-02858-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5792556PMC
January 2018

CpG Island Hypermethylation Mediated by DNMT3A Is a Consequence of AML Progression.

Cell 2017 02 16;168(5):801-816.e13. Epub 2017 Feb 16.

Section of Stem Cell Biology, Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; The McDonnell Genome Institute, Washington University, St. Louis, MO 63110, USA. Electronic address:

DNMT3A mutations occur in ∼25% of acute myeloid leukemia (AML) patients. The most common mutation, DNMT3A, has dominant negative activity that reduces DNA methylation activity by ∼80% in vitro. To understand the contribution of DNMT3A-dependent methylation to leukemogenesis, we performed whole-genome bisulfite sequencing of primary leukemic and non-leukemic cells in patients with or without DNMT3A mutations. Non-leukemic hematopoietic cells with DNMT3A displayed focal methylation loss, suggesting that hypomethylation antedates AML. Although virtually all AMLs with wild-type DNMT3A displayed CpG island hypermethylation, this change was not associated with gene silencing and was essentially absent in AMLs with DNMT3A mutations. Primary hematopoietic stem cells expanded with cytokines were hypermethylated in a DNMT3A-dependent manner, suggesting that hypermethylation may be a response to, rather than a cause of, cellular proliferation. Our findings suggest that hypomethylation is an initiating phenotype in AMLs with DNMT3A, while DNMT3A-dependent CpG island hypermethylation is a consequence of AML progression.
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http://dx.doi.org/10.1016/j.cell.2017.01.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5328582PMC
February 2017

TP53 and Decitabine in Acute Myeloid Leukemia and Myelodysplastic Syndromes.

N Engl J Med 2016 11;375(21):2023-2036

the Department of Internal Medicine, Division of Oncology (J.S.W., L.D.W., G.L.U., A.G., M.H.T., I.P., R.R., T.A.F., K.E.S.-G., R.V., S.T.O., C.N.A., A.F.C., M.A.S., M.A.J., S.E.H., K.L., M.R.J., M.J.W., P.W., D.C.L., J.F.D., T.J.L.), and the Division of Biostatistics (J.D.B.), and the Department of Pathology and Immunology (E.J.D., B.T., Y.-S.L.), Washington University School of Medicine, and McDonnell Genome Institute, Washington University in St. Louis (A.A.P., C.A.M., C.C.F., M.O., R.S.F., R.K.W., L.D.W., T.J.L.) - both in St. Louis; the Departments of Internal Medicine (A.H., N.K., M.J.S., W.S.) and Pharmacy (R.W.K.), University of Chicago, Chicago; and the Department of Internal Medicine (T.A.G.), Massachusetts General Hospital, Boston.

Background: The molecular determinants of clinical responses to decitabine therapy in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) are unclear.

Methods: We enrolled 84 adult patients with AML or MDS in a single-institution trial of decitabine to identify somatic mutations and their relationships to clinical responses. Decitabine was administered at a dose of 20 mg per square meter of body-surface area per day for 10 consecutive days in monthly cycles. We performed enhanced exome or gene-panel sequencing in 67 of these patients and serial sequencing at multiple time points to evaluate patterns of mutation clearance in 54 patients. An extension cohort included 32 additional patients who received decitabine in different protocols.

Results: Of the 116 patients, 53 (46%) had bone marrow blast clearance (<5% blasts). Response rates were higher among patients with an unfavorable-risk cytogenetic profile than among patients with an intermediate-risk or favorable-risk cytogenetic profile (29 of 43 patients [67%] vs. 24 of 71 patients [34%], P<0.001) and among patients with TP53 mutations than among patients with wild-type TP53 (21 of 21 [100%] vs. 32 of 78 [41%], P<0.001). Previous studies have consistently shown that patients with an unfavorable-risk cytogenetic profile and TP53 mutations who receive conventional chemotherapy have poor outcomes. However, in this study of 10-day courses of decitabine, neither of these risk factors was associated with a lower rate of overall survival than the rate of survival among study patients with intermediate-risk cytogenetic profiles.

Conclusions: Patients with AML and MDS who had cytogenetic abnormalities associated with unfavorable risk, TP53 mutations, or both had favorable clinical responses and robust (but incomplete) mutation clearance after receiving serial 10-day courses of decitabine. Although these responses were not durable, they resulted in rates of overall survival that were similar to those among patients with AML who had an intermediate-risk cytogenetic profile and who also received serial 10-day courses of decitabine. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT01687400 .).
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http://dx.doi.org/10.1056/NEJMoa1605949DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5217532PMC
November 2016

Comprehensive genomic analysis reveals FLT3 activation and a therapeutic strategy for a patient with relapsed adult B-lymphoblastic leukemia.

Exp Hematol 2016 Jul 13;44(7):603-13. Epub 2016 May 13.

Siteman Cancer Center, Washington University, St. Louis, MO, USA; Department of Medicine, Washington University, St. Louis, MO, USA.

The genomic events responsible for the pathogenesis of relapsed adult B-lymphoblastic leukemia (B-ALL) are not yet clear. We performed integrative analysis of whole-genome, whole-exome, custom capture, whole-transcriptome (RNA-seq), and locus-specific genomic assays across nine time points from a patient with primary de novo B-ALL. Comprehensive genome and transcriptome characterization revealed a dramatic tumor evolution during progression, yielding a tumor with complex clonal architecture at second relapse. We observed and validated point mutations in EP300 and NF1, a highly expressed EP300-ZNF384 gene fusion, a microdeletion in IKZF1, a focal deletion affecting SETD2, and large deletions affecting RB1, PAX5, NF1, and ETV6. Although the genome analysis revealed events of potential biological relevance, no clinically actionable treatment options were evident at the time of the second relapse. However, transcriptome analysis identified aberrant overexpression of the targetable protein kinase encoded by the FLT3 gene. Although the patient had refractory disease after salvage therapy for the second relapse, treatment with the FLT3 inhibitor sunitinib rapidly induced a near complete molecular response, permitting the patient to proceed to a matched-unrelated donor stem cell transplantation. The patient remains in complete remission more than 4 years later. Analysis of this patient's relapse genome revealed an unexpected, actionable therapeutic target that led to a specific therapy associated with a rapid clinical response. For some patients with relapsed or refractory cancers, this approach may indicate a novel therapeutic intervention that could alter outcome.
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http://dx.doi.org/10.1016/j.exphem.2016.04.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4914477PMC
July 2016

Rapid expansion of preexisting nonleukemic hematopoietic clones frequently follows induction therapy for de novo AML.

Blood 2016 Feb 2;127(7):893-7. Epub 2015 Dec 2.

Division of Oncology, Siteman Cancer Center, Washington University, St. Louis, MO; and.

There is interest in using leukemia-gene panels and next-generation sequencing to assess acute myelogenous leukemia (AML) response to induction chemotherapy. Studies have shown that patients with AML in morphologic remission may continue to have clonal hematopoiesis with populations closely related to the founding AML clone and that this confers an increased risk of relapse. However, it remains unknown how induction chemotherapy influences the clonal evolution of a patient's nonleukemic hematopoietic population. Here, we report that 5 of 15 patients with genetic clearance of their founding AML clone after induction chemotherapy had a concomitant expansion of a hematopoietic population unrelated to the initial AML. These populations frequently harbored somatic mutations in genes recurrently mutated in AML or myelodysplastic syndromes and were detectable at very low frequencies at the time of AML diagnosis. These results suggest that nonleukemic hematopoietic stem and progenitor cells, harboring specific aging-acquired mutations, may have a competitive fitness advantage after induction chemotherapy, expand, and persist long after the completion of chemotherapy. Although the clinical importance of these "rising" clones remains to be determined, it will be important to distinguish them from leukemia-related populations when assessing for molecular responses to induction chemotherapy.
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http://dx.doi.org/10.1182/blood-2015-10-677021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4760092PMC
February 2016

Genomic analysis of germ line and somatic variants in familial myelodysplasia/acute myeloid leukemia.

Blood 2015 Nov 22;126(22):2484-90. Epub 2015 Oct 22.

Massachusetts General Hospital Cancer Center, Boston, MA.

Familial clustering of myelodysplastic syndromes (MDSs) and acute myeloid leukemia (AML) can be caused by inherited factors. We screened 59 individuals from 17 families with 2 or more biological relatives with MDS/AML for variants in 12 genes with established roles in predisposition to MDS/AML, and identified a pathogenic germ line variant in 5 families (29%). Extending the screen with a panel of 264 genes that are recurrently mutated in de novo AML, we identified rare, nonsynonymous germ line variants in 4 genes, each segregating with MDS/AML in 2 families. Somatic mutations are required for progression to MDS/AML in these familial cases. Using a combination of targeted and exome sequencing of tumor and matched normal samples from 26 familial MDS/AML cases and asymptomatic carriers, we identified recurrent frameshift mutations in the cohesin-associated factor PDS5B, co-occurrence of somatic ASXL1 mutations with germ line GATA2 mutations, and recurrent mutations in other known MDS/AML drivers. Mutations in genes that are recurrently mutated in de novo AML were underrepresented in the familial MDS/AML cases, although the total number of somatic mutations per exome was the same. Lastly, clonal skewing of hematopoiesis was detected in 67% of young, asymptomatic RUNX1 carriers, providing a potential biomarker that could be used for surveillance in these high-risk families.
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http://dx.doi.org/10.1182/blood-2015-04-641100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4661171PMC
November 2015

Association Between Mutation Clearance After Induction Therapy and Outcomes in Acute Myeloid Leukemia.

JAMA 2015 Aug;314(8):811-22

Division of Oncology, Department of Medicine, Washington University School of Medicine, St Louis, Missouri.

Importance: Tests that predict outcomes for patients with acute myeloid leukemia (AML) are imprecise, especially for those with intermediate risk AML.

Objectives: To determine whether genomic approaches can provide novel prognostic information for adult patients with de novo AML.

Design, Setting, And Participants: Whole-genome or exome sequencing was performed on samples obtained at disease presentation from 71 patients with AML (mean age, 50.8 years) treated with standard induction chemotherapy at a single site starting in March 2002, with follow-up through January 2015. In addition, deep digital sequencing was performed on paired diagnosis and remission samples from 50 patients (including 32 with intermediate-risk AML), approximately 30 days after successful induction therapy. Twenty-five of the 50 were from the cohort of 71 patients, and 25 were new, additional cases.

Exposures: Whole-genome or exome sequencing and targeted deep sequencing. Risk of identification based on genetic data.

Main Outcomes And Measures: Mutation patterns (including clearance of leukemia-associated variants after chemotherapy) and their association with event-free survival and overall survival.

Results: Analysis of comprehensive genomic data from the 71 patients did not improve outcome assessment over current standard-of-care metrics. In an analysis of 50 patients with both presentation and documented remission samples, 24 (48%) had persistent leukemia-associated mutations in at least 5% of bone marrow cells at remission. The 24 with persistent mutations had significantly reduced event-free and overall survival vs the 26 who cleared all mutations. Patients with intermediate cytogenetic risk profiles had similar findings. [table: see text].

Conclusions And Relevance: The detection of persistent leukemia-associated mutations in at least 5% of bone marrow cells in day 30 remission samples was associated with a significantly increased risk of relapse, and reduced overall survival. These data suggest that this genomic approach may improve risk stratification for patients with AML.
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http://dx.doi.org/10.1001/jama.2015.9643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4621257PMC
August 2015

Role of TP53 mutations in the origin and evolution of therapy-related acute myeloid leukaemia.

Nature 2015 Feb 8;518(7540):552-555. Epub 2014 Dec 8.

The Genome Institute, Washington University in St. Louis, St. Louis, MO.

Therapy-related acute myeloid leukaemia (t-AML) and therapy-related myelodysplastic syndrome (t-MDS) are well-recognized complications of cytotoxic chemotherapy and/or radiotherapy. There are several features that distinguish t-AML from de novo AML, including a higher incidence of TP53 mutations, abnormalities of chromosomes 5 or 7, complex cytogenetics and a reduced response to chemotherapy. However, it is not clear how prior exposure to cytotoxic therapy influences leukaemogenesis. In particular, the mechanism by which TP53 mutations are selectively enriched in t-AML/t-MDS is unknown. Here, by sequencing the genomes of 22 patients with t-AML, we show that the total number of somatic single-nucleotide variants and the percentage of chemotherapy-related transversions are similar in t-AML and de novo AML, indicating that previous chemotherapy does not induce genome-wide DNA damage. We identified four cases of t-AML/t-MDS in which the exact TP53 mutation found at diagnosis was also present at low frequencies (0.003-0.7%) in mobilized blood leukocytes or bone marrow 3-6 years before the development of t-AML/t-MDS, including two cases in which the relevant TP53 mutation was detected before any chemotherapy. Moreover, functional TP53 mutations were identified in small populations of peripheral blood cells of healthy chemotherapy-naive elderly individuals. Finally, in mouse bone marrow chimaeras containing both wild-type and Tp53(+/-) haematopoietic stem/progenitor cells (HSPCs), the Tp53(+/-) HSPCs preferentially expanded after exposure to chemotherapy. These data suggest that cytotoxic therapy does not directly induce TP53 mutations. Rather, they support a model in which rare HSPCs carrying age-related TP53 mutations are resistant to chemotherapy and expand preferentially after treatment. The early acquisition of TP53 mutations in the founding HSPC clone probably contributes to the frequent cytogenetic abnormalities and poor responses to chemotherapy that are typical of patients with t-AML/t-MDS.
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http://dx.doi.org/10.1038/nature13968DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403236PMC
February 2015

Clonal architecture of secondary acute myeloid leukemia defined by single-cell sequencing.

PLoS Genet 2014 Jul 10;10(7):e1004462. Epub 2014 Jul 10.

Department of Internal Medicine, Division of Oncology, Washington University, St. Louis, Missouri, United States of America; Siteman Cancer Center, Washington University, St. Louis, Missouri, United States of America; Department of Pathology and Immunology, Washington University, St. Louis, Missouri, United States of America.

Next-generation sequencing has been used to infer the clonality of heterogeneous tumor samples. These analyses yield specific predictions-the population frequency of individual clones, their genetic composition, and their evolutionary relationships-which we set out to test by sequencing individual cells from three subjects diagnosed with secondary acute myeloid leukemia, each of whom had been previously characterized by whole genome sequencing of unfractionated tumor samples. Single-cell mutation profiling strongly supported the clonal architecture implied by the analysis of bulk material. In addition, it resolved the clonal assignment of single nucleotide variants that had been initially ambiguous and identified areas of previously unappreciated complexity. Accordingly, we find that many of the key assumptions underlying the analysis of tumor clonality by deep sequencing of unfractionated material are valid. Furthermore, we illustrate a single-cell sequencing strategy for interrogating the clonal relationships among known variants that is cost-effective, scalable, and adaptable to the analysis of both hematopoietic and solid tumors, or any heterogeneous population of cells.
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http://dx.doi.org/10.1371/journal.pgen.1004462DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4091781PMC
July 2014

Genomic and epigenomic landscapes of adult de novo acute myeloid leukemia.

N Engl J Med 2013 05 1;368(22):2059-74. Epub 2013 May 1.

Background: Many mutations that contribute to the pathogenesis of acute myeloid leukemia (AML) are undefined. The relationships between patterns of mutations and epigenetic phenotypes are not yet clear.

Methods: We analyzed the genomes of 200 clinically annotated adult cases of de novo AML, using either whole-genome sequencing (50 cases) or whole-exome sequencing (150 cases), along with RNA and microRNA sequencing and DNA-methylation analysis.

Results: AML genomes have fewer mutations than most other adult cancers, with an average of only 13 mutations found in genes. Of these, an average of 5 are in genes that are recurrently mutated in AML. A total of 23 genes were significantly mutated, and another 237 were mutated in two or more samples. Nearly all samples had at least 1 nonsynonymous mutation in one of nine categories of genes that are almost certainly relevant for pathogenesis, including transcription-factor fusions (18% of cases), the gene encoding nucleophosmin (NPM1) (27%), tumor-suppressor genes (16%), DNA-methylation-related genes (44%), signaling genes (59%), chromatin-modifying genes (30%), myeloid transcription-factor genes (22%), cohesin-complex genes (13%), and spliceosome-complex genes (14%). Patterns of cooperation and mutual exclusivity suggested strong biologic relationships among several of the genes and categories.

Conclusions: We identified at least one potential driver mutation in nearly all AML samples and found that a complex interplay of genetic events contributes to AML pathogenesis in individual patients. The databases from this study are widely available to serve as a foundation for further investigations of AML pathogenesis, classification, and risk stratification. (Funded by the National Institutes of Health.).
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http://dx.doi.org/10.1056/NEJMoa1301689DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767041PMC
May 2013

The origin and evolution of mutations in acute myeloid leukemia.

Cell 2012 Jul;150(2):264-78

Department of Medicine, Washington University, St. Louis, MO 63110, USA.

Most mutations in cancer genomes are thought to be acquired after the initiating event, which may cause genomic instability and drive clonal evolution. However, for acute myeloid leukemia (AML), normal karyotypes are common, and genomic instability is unusual. To better understand clonal evolution in AML, we sequenced the genomes of M3-AML samples with a known initiating event (PML-RARA) versus the genomes of normal karyotype M1-AML samples and the exomes of hematopoietic stem/progenitor cells (HSPCs) from healthy people. Collectively, the data suggest that most of the mutations found in AML genomes are actually random events that occurred in HSPCs before they acquired the initiating mutation; the mutational history of that cell is "captured" as the clone expands. In many cases, only one or two additional, cooperating mutations are needed to generate the malignant founding clone. Cells from the founding clone can acquire additional cooperating mutations, yielding subclones that can contribute to disease progression and/or relapse.
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http://dx.doi.org/10.1016/j.cell.2012.06.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407563PMC
July 2012

Clonal architecture of secondary acute myeloid leukemia.

N Engl J Med 2012 Mar 14;366(12):1090-8. Epub 2012 Mar 14.

Department of Internal Medicine, Division of Oncology, Washington University School of Medicine, St. Louis, MO 63110, USA.

Background: The myelodysplastic syndromes are a group of hematologic disorders that often evolve into secondary acute myeloid leukemia (AML). The genetic changes that underlie progression from the myelodysplastic syndromes to secondary AML are not well understood.

Methods: We performed whole-genome sequencing of seven paired samples of skin and bone marrow in seven subjects with secondary AML to identify somatic mutations specific to secondary AML. We then genotyped a bone marrow sample obtained during the antecedent myelodysplastic-syndrome stage from each subject to determine the presence or absence of the specific somatic mutations. We identified recurrent mutations in coding genes and defined the clonal architecture of each pair of samples from the myelodysplastic-syndrome stage and the secondary-AML stage, using the allele burden of hundreds of mutations.

Results: Approximately 85% of bone marrow cells were clonal in the myelodysplastic-syndrome and secondary-AML samples, regardless of the myeloblast count. The secondary-AML samples contained mutations in 11 recurrently mutated genes, including 4 genes that have not been previously implicated in the myelodysplastic syndromes or AML. In every case, progression to acute leukemia was defined by the persistence of an antecedent founding clone containing 182 to 660 somatic mutations and the outgrowth or emergence of at least one subclone, harboring dozens to hundreds of new mutations. All founding clones and subclones contained at least one mutation in a coding gene.

Conclusions: Nearly all the bone marrow cells in patients with myelodysplastic syndromes and secondary AML are clonally derived. Genetic evolution of secondary AML is a dynamic process shaped by multiple cycles of mutation acquisition and clonal selection. Recurrent gene mutations are found in both founding clones and daughter subclones. (Funded by the National Institutes of Health and others.).
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http://dx.doi.org/10.1056/NEJMoa1106968DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3320218PMC
March 2012

Clonal evolution in relapsed acute myeloid leukaemia revealed by whole-genome sequencing.

Nature 2012 Jan 11;481(7382):506-10. Epub 2012 Jan 11.

The Genome Institute, Washington University, St Louis, Missouri 63108, USA.

Most patients with acute myeloid leukaemia (AML) die from progressive disease after relapse, which is associated with clonal evolution at the cytogenetic level. To determine the mutational spectrum associated with relapse, we sequenced the primary tumour and relapse genomes from eight AML patients, and validated hundreds of somatic mutations using deep sequencing; this allowed us to define clonality and clonal evolution patterns precisely at relapse. In addition to discovering novel, recurrently mutated genes (for example, WAC, SMC3, DIS3, DDX41 and DAXX) in AML, we also found two major clonal evolution patterns during AML relapse: (1) the founding clone in the primary tumour gained mutations and evolved into the relapse clone, or (2) a subclone of the founding clone survived initial therapy, gained additional mutations and expanded at relapse. In all cases, chemotherapy failed to eradicate the founding clone. The comparison of relapse-specific versus primary tumour mutations in all eight cases revealed an increase in transversions, probably due to DNA damage caused by cytotoxic chemotherapy. These data demonstrate that AML relapse is associated with the addition of new mutations and clonal evolution, which is shaped, in part, by the chemotherapy that the patients receive to establish and maintain remissions.
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http://dx.doi.org/10.1038/nature10738DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3267864PMC
January 2012

Recurrent mutations in the U2AF1 splicing factor in myelodysplastic syndromes.

Nat Genet 2011 Dec 11;44(1):53-7. Epub 2011 Dec 11.

Department of Internal Medicine, Division of Oncology, Washington University, St. Louis, Missouri, USA.

Myelodysplastic syndromes (MDS) are hematopoietic stem cell disorders that often progress to chemotherapy-resistant secondary acute myeloid leukemia (sAML). We used whole-genome sequencing to perform an unbiased comprehensive screen to discover the somatic mutations in a sample from an individual with sAML and genotyped the loci containing these mutations in the matched MDS sample. Here we show that a missense mutation affecting the serine at codon 34 (Ser34) in U2AF1 was recurrently present in 13 out of 150 (8.7%) subjects with de novo MDS, and we found suggestive evidence of an increased risk of progression to sAML associated with this mutation. U2AF1 is a U2 auxiliary factor protein that recognizes the AG splice acceptor dinucleotide at the 3' end of introns, and the alterations in U2AF1 are located in highly conserved zinc fingers of this protein. Mutant U2AF1 promotes enhanced splicing and exon skipping in reporter assays in vitro. This previously unidentified, recurrent mutation in U2AF1 implicates altered pre-mRNA splicing as a potential mechanism for MDS pathogenesis.
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http://dx.doi.org/10.1038/ng.1031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3247063PMC
December 2011

Use of whole-genome sequencing to diagnose a cryptic fusion oncogene.

JAMA 2011 Apr;305(15):1577-84

Department of Medicine, Washington University, St Louis, Missouri, USA.

Context: Whole-genome sequencing is becoming increasingly available for research purposes, but it has not yet been routinely used for clinical diagnosis.

Objective: To determine whether whole-genome sequencing can identify cryptic, actionable mutations in a clinically relevant time frame.

Design, Setting, And Patient: We were referred a difficult diagnostic case of acute promyelocytic leukemia with no pathogenic X-RARA fusion identified by routine metaphase cytogenetics or interphase fluorescence in situ hybridization (FISH). The case patient was enrolled in an institutional review board-approved protocol, with consent specifically tailored to the implications of whole-genome sequencing. The protocol uses a "movable firewall" that maintains patient anonymity within the entire research team but allows the research team to communicate medically relevant information to the treating physician.

Main Outcome Measures: Clinical relevance of whole-genome sequencing and time to communicate validated results to the treating physician.

Results: Massively parallel paired-end sequencing allowed identification of a cytogenetically cryptic event: a 77-kilobase segment from chromosome 15 was inserted en bloc into the second intron of the RARA gene on chromosome 17, resulting in a classic bcr3 PML-RARA fusion gene. Reverse transcription polymerase chain reaction sequencing subsequently validated the expression of the fusion transcript. Novel FISH probes identified 2 additional cases of t(15;17)-negative acute promyelocytic leukemia that had cytogenetically invisible insertions. Whole-genome sequencing and validation were completed in 7 weeks and changed the treatment plan for the patient.

Conclusion: Whole-genome sequencing can identify cytogenetically invisible oncogenes in a clinically relevant time frame.
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http://dx.doi.org/10.1001/jama.2011.497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3156695PMC
April 2011

Identification of a novel TP53 cancer susceptibility mutation through whole-genome sequencing of a patient with therapy-related AML.

JAMA 2011 Apr;305(15):1568-76

Department of Medicine, Siteman Cancer Center, Washington University, St Louis, Missouri, USA.

Context: The identification of patients with inherited cancer susceptibility syndromes facilitates early diagnosis, prevention, and treatment. However, in many cases of suspected cancer susceptibility, the family history is unclear and genetic testing of common cancer susceptibility genes is unrevealing.

Objective: To apply whole-genome sequencing to a patient without any significant family history of cancer but with suspected increased cancer susceptibility because of multiple primary tumors to identify rare or novel germline variants in cancer susceptibility genes. DESIGN, SETTING, AND PARTICIPANT: Skin (normal) and bone marrow (leukemia) DNA were obtained from a patient with early-onset breast and ovarian cancer (negative for BRCA1 and BRCA2 mutations) and therapy-related acute myeloid leukemia (t-AML) and analyzed with the following: whole-genome sequencing using paired-end reads, single-nucleotide polymorphism (SNP) genotyping, RNA expression profiling, and spectral karyotyping.

Main Outcome Measures: Structural variants, copy number alterations, single-nucleotide variants, and small insertions and deletions (indels) were detected and validated using the described platforms. RESULTS; Whole-genome sequencing revealed a novel, heterozygous 3-kilobase deletion removing exons 7-9 of TP53 in the patient's normal skin DNA, which was homozygous in the leukemia DNA as a result of uniparental disomy. In addition, a total of 28 validated somatic single-nucleotide variations or indels in coding genes, 8 somatic structural variants, and 12 somatic copy number alterations were detected in the patient's leukemia genome.

Conclusion: Whole-genome sequencing can identify novel, cryptic variants in cancer susceptibility genes in addition to providing unbiased information on the spectrum of mutations in a cancer genome.
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http://dx.doi.org/10.1001/jama.2011.473DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3170052PMC
April 2011

DNMT3A mutations in acute myeloid leukemia.

N Engl J Med 2010 Dec 10;363(25):2424-33. Epub 2010 Nov 10.

Department of Genetics, Genome Center, Washington University, St Louis, MO 63110, USA.

Background: The genetic alterations responsible for an adverse outcome in most patients with acute myeloid leukemia (AML) are unknown.

Methods: Using massively parallel DNA sequencing, we identified a somatic mutation in DNMT3A, encoding a DNA methyltransferase, in the genome of cells from a patient with AML with a normal karyotype. We sequenced the exons of DNMT3A in 280 additional patients with de novo AML to define recurring mutations.

Results: A total of 62 of 281 patients (22.1%) had mutations in DNMT3A that were predicted to affect translation. We identified 18 different missense mutations, the most common of which was predicted to affect amino acid R882 (in 37 patients). We also identified six frameshift, six nonsense, and three splice-site mutations and a 1.5-Mbp deletion encompassing DNMT3A. These mutations were highly enriched in the group of patients with an intermediate-risk cytogenetic profile (56 of 166 patients, or 33.7%) but were absent in all 79 patients with a favorable-risk cytogenetic profile (P<0.001 for both comparisons). The median overall survival among patients with DNMT3A mutations was significantly shorter than that among patients without such mutations (12.3 months vs. 41.1 months, P<0.001). DNMT3A mutations were associated with adverse outcomes among patients with an intermediate-risk cytogenetic profile or FLT3 mutations, regardless of age, and were independently associated with a poor outcome in Cox proportional-hazards analysis.

Conclusions: DNMT3A mutations are highly recurrent in patients with de novo AML with an intermediate-risk cytogenetic profile and are independently associated with a poor outcome. (Funded by the National Institutes of Health and others.).
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http://dx.doi.org/10.1056/NEJMoa1005143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3201818PMC
December 2010

Recurring mutations found by sequencing an acute myeloid leukemia genome.

N Engl J Med 2009 Sep 5;361(11):1058-66. Epub 2009 Aug 5.

Department of Genetics, Washington University, St. Louis, MO 63110, USA.

Background: The full complement of DNA mutations that are responsible for the pathogenesis of acute myeloid leukemia (AML) is not yet known.

Methods: We used massively parallel DNA sequencing to obtain a very high level of coverage (approximately 98%) of a primary, cytogenetically normal, de novo genome for AML with minimal maturation (AML-M1) and a matched normal skin genome.

Results: We identified 12 acquired (somatic) mutations within the coding sequences of genes and 52 somatic point mutations in conserved or regulatory portions of the genome. All mutations appeared to be heterozygous and present in nearly all cells in the tumor sample. Four of the 64 mutations occurred in at least 1 additional AML sample in 188 samples that were tested. Mutations in NRAS and NPM1 had been identified previously in patients with AML, but two other mutations had not been identified. One of these mutations, in the IDH1 gene, was present in 15 of 187 additional AML genomes tested and was strongly associated with normal cytogenetic status; it was present in 13 of 80 cytogenetically normal samples (16%). The other was a nongenic mutation in a genomic region with regulatory potential and conservation in higher mammals; we detected it in one additional AML tumor. The AML genome that we sequenced contains approximately 750 point mutations, of which only a small fraction are likely to be relevant to pathogenesis.

Conclusions: By comparing the sequences of tumor and skin genomes of a patient with AML-M1, we have identified recurring mutations that may be relevant for pathogenesis.
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http://dx.doi.org/10.1056/NEJMoa0903840DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3201812PMC
September 2009

Acquired copy number alterations in adult acute myeloid leukemia genomes.

Proc Natl Acad Sci U S A 2009 Aug 27;106(31):12950-5. Epub 2009 Jul 27.

Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.

Cytogenetic analysis of acute myeloid leukemia (AML) cells has accelerated the identification of genes important for AML pathogenesis. To complement cytogenetic studies and to identify genes altered in AML genomes, we performed genome-wide copy number analysis with paired normal and tumor DNA obtained from 86 adult patients with de novo AML using 1.85 million feature SNP arrays. Acquired copy number alterations (CNAs) were confirmed using an ultra-dense array comparative genomic hybridization platform. A total of 201 somatic CNAs were found in the 86 AML genomes (mean, 2.34 CNAs per genome), with French-American-British system M6 and M7 genomes containing the most changes (10-29 CNAs per genome). Twenty-four percent of AML patients with normal cytogenetics had CNA, whereas 40% of patients with an abnormal karyotype had additional CNA detected by SNP array, and several CNA regions were recurrent. The mRNA expression levels of 57 genes were significantly altered in 27 of 50 recurrent CNA regions <5 megabases in size. A total of 8 uniparental disomy (UPD) segments were identified in the 86 genomes; 6 of 8 UPD calls occurred in samples with a normal karyotype. Collectively, 34 of 86 AML genomes (40%) contained alterations not found with cytogenetics, and 98% of these regions contained genes. Of 86 genomes, 43 (50%) had no CNA or UPD at this level of resolution. In this study of 86 adult AML genomes, the use of an unbiased high-resolution genomic screen identified many genes not previously implicated in AML that may be relevant for pathogenesis, along with many known oncogenes and tumor suppressor genes.
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http://dx.doi.org/10.1073/pnas.0903091106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2716381PMC
August 2009

DNA sequencing of a cytogenetically normal acute myeloid leukaemia genome.

Nature 2008 Nov;456(7218):66-72

Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63108, USA.

Acute myeloid leukaemia is a highly malignant haematopoietic tumour that affects about 13,000 adults in the United States each year. The treatment of this disease has changed little in the past two decades, because most of the genetic events that initiate the disease remain undiscovered. Whole-genome sequencing is now possible at a reasonable cost and timeframe to use this approach for the unbiased discovery of tumour-specific somatic mutations that alter the protein-coding genes. Here we present the results obtained from sequencing a typical acute myeloid leukaemia genome, and its matched normal counterpart obtained from the same patient's skin. We discovered ten genes with acquired mutations; two were previously described mutations that are thought to contribute to tumour progression, and eight were new mutations present in virtually all tumour cells at presentation and relapse, the function of which is not yet known. Our study establishes whole-genome sequencing as an unbiased method for discovering cancer-initiating mutations in previously unidentified genes that may respond to targeted therapies.
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http://dx.doi.org/10.1038/nature07485DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2603574PMC
November 2008

Somatic mutations and germline sequence variants in the expressed tyrosine kinase genes of patients with de novo acute myeloid leukemia.

Blood 2008 May 12;111(9):4797-808. Epub 2008 Feb 12.

Division of Oncology, Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, USA.

Activating mutations in tyrosine kinase (TK) genes (eg, FLT3 and KIT) are found in more than 30% of patients with de novo acute myeloid leukemia (AML); many groups have speculated that mutations in other TK genes may be present in the remaining 70%. We performed high-throughput resequencing of the kinase domains of 26 TK genes (11 receptor TK; 15 cytoplasmic TK) expressed in most AML patients using genomic DNA from the bone marrow (tumor) and matched skin biopsy samples ("germline") from 94 patients with de novo AML; sequence variants were validated in an additional 94 AML tumor samples (14.3 million base pairs of sequence were obtained and analyzed). We identified known somatic mutations in FLT3, KIT, and JAK2 TK genes at the expected frequencies and found 4 novel somatic mutations, JAK1(V623A), JAK1(T478S), DDR1(A803V), and NTRK1(S677N), once each in 4 respective patients of 188 tested. We also identified novel germline sequence changes encoding amino acid substitutions (ie, nonsynonymous changes) in 14 TK genes, including TYK2, which had the largest number of nonsynonymous sequence variants (11 total detected). Additional studies will be required to define the roles that these somatic and germline TK gene variants play in AML pathogenesis.
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http://dx.doi.org/10.1182/blood-2007-09-113027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2343607PMC
May 2008

Identification of somatic JAK1 mutations in patients with acute myeloid leukemia.

Blood 2008 May 26;111(9):4809-12. Epub 2007 Dec 26.

Department of Medicine, Washington University School of Medicine, St Louis, St Louis, MO 63110, USA.

Somatic mutations in JAK2 are frequently found in myeloproliferative diseases, and gain-of-function JAK3 alleles have been identified in M7 acute myeloid leukemia (AML), but a role for JAK1 in AML has not been described. We screened the entire coding region of JAK1 by total exonic resequencing of bone marrow DNA samples from 94 patients with de novo AML. We identified 2 novel somatic mutations in highly conserved residues of the JAK1 gene (T478S, V623A), in 2 separate patients and confirmed these by resequencing germ line DNA samples from the same patients. Overexpression of mutant JAK1 did not transform primary murine cells in standard assays, but compared with wild-type JAK1, JAK1(T478S), and JAK1(V623A) expression was associated with increased STAT1 activation in response to type I interferon and activation of multiple downstream signaling pathways. This is the first report to demonstrate somatic JAK1 mutations in AML and suggests that JAK1 mutations may function as disease-modifying mutations in AML pathogenesis.
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http://dx.doi.org/10.1182/blood-2007-05-090308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2343608PMC
May 2008

A pilot study of high-throughput, sequence-based mutational profiling of primary human acute myeloid leukemia cell genomes.

Proc Natl Acad Sci U S A 2003 Nov 12;100(24):14275-80. Epub 2003 Nov 12.

Department of Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA.

In this pilot study, we used primary human acute myeloid leukemia (AML) cell genomes as templates for exonic PCR amplification, followed by high-throughput resequencing, analyzing approximately 7 million base pairs of DNA from 140 AML samples and 48 controls. We identified six previously described, and seven previously undescribed sequence changes that may be relevant for AML pathogenesis. Because the sequencing templates were generated from primary AML cells, the technique favors the detection of mutations from the most dominant clones within the tumor cell mixture. This strategy represents a viable approach for the detection of potentially relevant, nonrandom mutations in primary human cancer cell genomes.
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http://dx.doi.org/10.1073/pnas.2335924100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC283582PMC
November 2003