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Rinaldi I, Louisa M, Mulya Sari R, Arwanih E. FLT3-ITD Mutation and FLT3 Ligand Plasma Level Were Not Associated with One-Year Survival of Indonesian Acute Myeloid Leukemia Patients. Onco Targets Ther 2021; 14:1479-1486. [PMID: 33664580 PMCID: PMC7924121 DOI: 10.2147/ott.s282842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 12/23/2020] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVE To analyze the association of FLT3-ITD mutation and FLT3 ligand plasma level with one-year survival of Indonesian acute myeloid leukemia (AML) patients. METHODS A prospective cohort study was conducted to determine the association between FLT-3-ITD mutation and FLT3 ligand plasma level with one-year survival of Indonesian AML patients. In the study, a total of 51 AML patients were obtained from two tertiary hospitals in Indonesia from year 2018 to 2020. Inclusion criteria were de novo AML male and female patients aged ≥18 years old. Exclusion criteria were prior myelodysplastic syndrome and patients that refused to participate in the study. FLT3-ITD genotype of patients was then analyzed using PCR method while FLT3 ligand plasma level was measured using ELISA method. Patients were then followed-up for 1 year or until death occurred with survival as the measured outcome. Association between independent and dependent variable were analyzed by cox regression proportional hazard. RESULTS Eleven patients (21.5%) in this study had FLT3-ITD mutation. The median age of AML patients was 45 (18-71) years, and the median blast percentage was 50% (5-87%). After one-year follow-up, 33 (64.7%) patients had died. The median survival of AML patients was 6 months. Univariate analysis showed no association between FLT3-ITD mutation status (HR: 1.051 ; 95% CI: 0.483-2.286; P: 0.901) and FLT3 ligand plasma level (HR: 0.798; 95% CI: 0.347-1.837; p= 0.596), and age (HR: 1.283; 95% CI: 0.575-2.862; p= 0.542) with one-year survival of AML patients, but multivariate analysis showed association between GFR with one-year survival of AML patients in this cohort (HR: 4.053; 95% CI: 1.469-11.183; p= 0.007). CONCLUSION One-year survival of AML patients in Indonesia is not affected by FLT3-ITD mutation and FLT3 ligand plasma level. However, GFR showed association with one-year survival of AML patient in this cohort study.
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Affiliation(s)
- Ikhwan Rinaldi
- Division of Hematology and Medical Oncology, Department of Internal Medicine, Cipto Mangunkusumo National General Hospital, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Melva Louisa
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Resti Mulya Sari
- Division of Hematology and Medical Oncology, Department of Internal Medicine, Dharmais Cancer Hospital,Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Elly Arwanih
- Division of Hematology and Medical Oncology, Department of Internal Medicine, Cipto Mangunkusumo National General Hospital, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
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Jin A, Feng J, Wei G, Wu W, Yang L, Xu H, Zhang Y, Cui J, Chang AH, Hu Y, Huang H. CD19/CD22 chimeric antigen receptor T-cell therapy for refractory acute B-cell lymphoblastic leukemia with FLT3-ITD mutations. Bone Marrow Transplant 2020; 55:717-721. [DOI: 10.1038/s41409-020-0807-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/14/2020] [Accepted: 01/21/2020] [Indexed: 11/09/2022]
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Nguyen B, Williams AB, Young DJ, Ma H, Li L, Levis M, Brown P, Small D. FLT3 activating mutations display differential sensitivity to multiple tyrosine kinase inhibitors. Oncotarget 2017; 8:10931-10944. [PMID: 28077790 PMCID: PMC5355235 DOI: 10.18632/oncotarget.14539] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 12/25/2016] [Indexed: 11/25/2022] Open
Abstract
Fms-like tyrosine kinase-3 (FLT3) is a receptor tyrosine kinase that normally functions in hematopoietic cell survival, proliferation and differentiation. Constitutively activating mutations of FLT3 map predominately to the juxtamembrane domain (internal tandem duplications; ITD) or the activation loop (AL) of the kinase domain and are detected in about 1/3 of de novo acute myeloid leukemia (AML) patients. Small molecule tyrosine kinase inhibitors (TKI) effectively target FLT3/ITD mutations, but some activating mutations, particularly those on the AL, are relatively resistant to many FLT3 TKI. We reproduced many of the AL or other non-ITD activating mutations and tested 13 FLT3 TKI for their activity against these and wild-type FLT3. All 13 TKI tested inhibited BaF3/ITD cell proliferation in a concentration-dependent manner as reported, but most TKI exhibited a wide range of differential activity against AL and other point mutants. Western blotting results examining inhibition of FLT3 autophosphorylation and signaling pathways indicate that many AL mutations reduce TKI binding. Most FLT3 TKI effectively target wild-type FLT3 signaling. As a demonstration of this differential activity, treatment of BaF3 D835Y cells transplanted in BALB/c mice with sorafenib showed no effect in vivo against this mutant whereas lestaurtinib proved effective at reducing disease burden. Thus, while FLT3 TKI have been selected based on their ability to inhibit FLT3/ITD, the selection of appropriate TKI for AML patients with FLT3 AL and other activating point mutations requires personalized consideration.
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Affiliation(s)
- Bao Nguyen
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Allen B Williams
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David J Young
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pediatrics Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hayley Ma
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Li Li
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mark Levis
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Patrick Brown
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pediatrics Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Donald Small
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pediatrics Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Profiling gene mutations, translocations, and multidrug resistance in pediatric acute lymphoblastic leukemia: a step forward to personalizing medicine. Med Oncol 2016; 33:98. [DOI: 10.1007/s12032-016-0809-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/09/2016] [Indexed: 12/23/2022]
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5
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FLT3 Internal Tandem Duplication and D835 Mutations in Patients with Acute Lymphoblastic Leukemia and its Clinical Significance. Mediterr J Hematol Infect Dis 2014; 6:e2014038. [PMID: 24959335 PMCID: PMC4063605 DOI: 10.4084/mjhid.2014.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 05/09/2014] [Indexed: 12/26/2022] Open
Abstract
The fms-like tyrosine kinase 3 (FLT3) gene is a member of the class III receptor tyrosine kinase family. Mutations of FLT3 were first described in 1997 and account for the most frequent molecular mutations in acute myeloid leukemia. Currently, there is no published data on FLT3 mutations in Saudi acute lymphoblastic leukemia (ALL) patients. In this retrospective study, we have examined a cohort of 77 ALL patients to determine the prevalence of FLT3 mutations and the possible prognostic relevance of these mutations in ALL patients. Correlations to other biologic factors such as karyotype, molecular mutations, and leukocyte count were also considered. FLT3 internal tandem duplication (ITD) mutations and point mutation in tyrosine kinase domain (D835) were analyzed in ALL patients, at diagnosis, by polymerase chain reaction (PCR). Two cases (2.6%, 2/77) were positive for FLT3 mutations; one was found to have FLT3/ITD and the other FLT3/D835. Our findings suggest that FLT3 mutations are not common in Saudi ALL and do not affect clinical outcome.
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Annamaneni S, Kagita S, Gorre M, Digumarti RR, Satti V, Battini MR. Incidence of internal tandem duplications and D835 mutations of FLT3 gene in chronic myeloid leukemia patients from Southern India. ACTA ACUST UNITED AC 2013; 19:129-35. [PMID: 23796006 DOI: 10.1179/1607845413y.0000000109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE To screen two important FLT3 mutations (internal tandem duplication (ITD) and D835 point mutations) in chronic myeloid leukemia (CML) patients from Southern India and report their incidence. METHODS Screened 350 CML patients and 350 controls for the two FLT3/mutations through polymerase chain reaction and restriction fragment length polymorphism methods. RESULTS ITDs were detected in 12 of the 350 CML patients (3.4%) and D835 mutations in only four cases (1.14%), relatively low in frequency as compared to those reported earlier from non-Indian populations. None of the cases showed simultaneous occurence of both ITD and D835 mutations. DISCUSSION These FLT3 mutations seem to be very rare in CML, and it is possible that these could be found only in a subset of patients who are in the progressive stage and/or with varied drug response. Prospective studies are needed to confirm the role of FLT3 mutations in CML pathogenesis, which may help devising therapeutic interventions.
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Kraszewska MD, Dawidowska M, Kosmalska M, Sędek L, Grzeszczak W, Kowalczyk JR, Szczepański T, Witt M. BCL11B, FLT3, NOTCH1 and FBXW7 mutation status in T-cell acute lymphoblastic leukemia patients. Blood Cells Mol Dis 2012; 50:33-8. [PMID: 23040356 DOI: 10.1016/j.bcmd.2012.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
Abstract
T-cell acute lymphoblastic leukemia is a heterogeneous malignancy originating from developing lymphocyte precursors likely due to mutations in genes regulating thymocyte differentiation. Here, we characterized mutation status of BCL11B and FLT3 genes, presumably involved in T-ALL, together with FBXW7 and NOTCH1 as known players in T-ALL in 65 pediatric T-cell acute lymphoblastic leukemia patients. We also aimed at the assessment of prognostic value of NOTCH1 and FBXW7 mutations in ALL-IC BFM 2002 protocol. FLT3 and BCL11B mutations were detected in 3% and 2% of patients, respectively. FBXW7 mutations were observed in 8% of patients, while NOTCH1 was mutated in 40%. No correlation was found between NOTCH1 and FBXW7 mutations and traditionally used clinical factors or molecular features. In total we have detected nine mutations, which have not been previously described by others. Eight of them were found in NOTCH1 and one in BCL11B gene. Observed frequencies of NOTCH1 and FBXW7 are in line with previous reports, thus confirming postulated participation of these two genes in T-ALL pathomechanism. Moreover, we report on mutation frequency of FLT3 and BCL11B, not extensively studied in T-ALL so far. Finally, we suggest a putative role of BLC11B as an oncogene in T-ALL pathogenesis.
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Affiliation(s)
- Monika D Kraszewska
- Department of Molecular and Clinical Genetics, Institute of Human Genetics, Polish Academy of Sciences, Poznań, Poland
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Kraszewska MD, Dawidowska M, Szczepański T, Witt M. T-cell acute lymphoblastic leukaemia: recent molecular biology findings. Br J Haematol 2011; 156:303-15. [PMID: 22145858 DOI: 10.1111/j.1365-2141.2011.08957.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
For many years, T-cell acute lymphoblastic leukaemia (T-ALL) has been considered and treated as a single malignancy, but divergent outcomes in T-ALL patients receiving uniform treatment protocols encouraged intensive research on the molecular biology of this disease. Recent findings in the field demonstrate that T-ALL is much more heterogeneous than originally believed and extremely diverse outcomes of patients require refinement of T-ALL classification, leading to subtype-specific adjustment of treatment. Many different biological features of T-ALL blast cells have recently been found to contribute to disease development and patient outcome and their analysis could potentially be introduced into improved diagnostics and classification of the disease. This review focuses on five key issues of T-ALL biology: chromosome aberrations, gene expression profiles, gene mutations, DNA methylation patterns, and immunoglobulin/T cell receptor (Ig/TCR) gene rearrangements. Additionally, molecular monitoring of minimal residual disease, by far the most reliable independent prognostic factor in T-ALL, has been highlighted in the context of Ig/TCR gene rearrangements. Translation of this biological information into better prognostic classification and more effective treatment should lead to improvement of outcome in T-ALL patients.
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Affiliation(s)
- Monika D Kraszewska
- Department of Molecular and Clinical Genetics, Institute of Human Genetics, Polish Academy of Sciences, Poznań, Poland.
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Takahashi S. Downstream molecular pathways of FLT3 in the pathogenesis of acute myeloid leukemia: biology and therapeutic implications. J Hematol Oncol 2011; 4:13. [PMID: 21453545 PMCID: PMC3076284 DOI: 10.1186/1756-8722-4-13] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 04/01/2011] [Indexed: 01/13/2023] Open
Abstract
FLT3 is a type III receptor tyrosine kinase. Mutations of FLT3 comprise one of the most frequently identified types of genetic alterations in acute myeloid leukemia. One-third of acute myeloid leukemia patients have mutations of this gene, and the majority of these mutations involve an internal tandem duplication in the juxtamembrane region of FLT3, leading to constitutive activation of downstream signaling pathways and aberrant cell growth. This review summarizes the current understanding of the effects of the downstream molecular signaling pathways after FLT3 activation, with a particular focus on the effects on transcription factors. Moreover, this review describes novel FLT3-targeted therapies, as well as efficient combination therapies for FLT3-mutated leukemia cells.
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Affiliation(s)
- Shinichiro Takahashi
- The Division of Molecular Hematology, Kitasato University Graduate School of Medical Sciences, 1-15-1 Kitasato, Minami-ku, Sagamihara 252-0373, Japan.
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Vora HH, Shukla SN, Brahambhatt BV, Mehta SH, Patel NA, Parikh SK, Shah KN, Shah PM. Clinical relevance of FLT3 receptor protein expression in Indian patients with acute leukemia. Asia Pac J Clin Oncol 2010; 6:306-19. [PMID: 21114781 DOI: 10.1111/j.1743-7563.2010.01322.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM FLT3 is a receptor tyrosine kinase that plays an important role in the pathogenesis of leukemia. The present study aimed to evaluate the role of FLT3 protein in patients with acute leukemia. METHOD FLT3 protein was quantified by flow cytometry on leukemic blasts using CD135 antibody in 160 patients with acute leukemia. RESULTS We demonstrated FLT3 protein expression (>20%) in 82% of acute myeloid leukemia (AML), 60% of B-lineage acute lymphoblastic leukemia (B-ALL), 23% of T-lineage acute lymphoblastic leukemia (T-ALL) and 80% of biphenotypic leukemia. Further, FLT3 expression was seen to be significantly higher in AMLM2, M4, and M5 than in AMLM3. In B-ALL, FLT3 was found to be higher in pro-B-ALL and lower in early B-ALL. A CD34 expression >20% was associated with FLT3 positive B-ALL. When correlated with disease status, all patients in the relapsed AML group had FLT3 > 20% at diagnosis. Unlike AML, the relapsed group of B-ALL showed a lower incidence of FLT3 than the remission group. CONCLUSION In summary, our data imply that there is frequent overexpression of the FLT3 protein in AML and B-ALL patients of Indian origin. In future, the FLT3 protein level may be used to select patients for whom FLT3 inhibitor therapy may be indicated.
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Affiliation(s)
- Hemangini H Vora
- Immunohistochemistry and Flowcytometry Division, The Gujarat Cancer and Research Institute, New Civil Hospital Compound, Asarwa, Ahmedabad, India.
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Shook D, Coustan-Smith E, Ribeiro RC, Rubnitz JE, Campana D. Minimal residual disease quantitation in acute myeloid leukemia. ACTA ACUST UNITED AC 2010; 9 Suppl 3:S281-5. [PMID: 19778853 DOI: 10.3816/clm.2009.s.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The prognosis for patients with acute myeloid leukemia (AML) is heterogeneous. A minority of patients have clinical and biologic features associated with a very high risk of relapse. For the remaining patients, no clear prognostic factors can be identified at diagnosis. The degree of treatment response is likely to be an informative predictor of outcome for these patients. Modern assays to detect AML cells that are undetectable by conventional morphologic techniques, ie, minimal residual disease (MRD), can potentially improve measurements of treatment response. It is plausible that modifications to treatment based on the results of these assays will improve clinical management and ultimately increase cure rates. Established MRD assays for AML are based on either polymerase chain reaction amplification of genetic abnormalities or flow cytometric detection of abnormal immunophenotypes. Residual disease and treatment response can be measured by these assays in a manner that is much more sensitive and objective than that afforded by conventional morphologic examination. The expanding use of MRD testing is beginning to change the definitions of treatment response and of remission. Other clinically informative uses of MRD testing include the detection of early relapse and the evaluation of the efficacy of new antileukemic agents.
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Affiliation(s)
- David Shook
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
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Monosomies 7p and 12p and FLT3 internal tandem duplication: possible markers for diagnosis of T/myeloid biphenotypic acute leukemia and its clonal evolution. Int J Hematol 2009; 89:352-358. [DOI: 10.1007/s12185-009-0268-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 01/26/2009] [Accepted: 02/04/2009] [Indexed: 10/21/2022]
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Mori S, Cortes J, Kantarjian H, Zhang W, Andreef M, Ravandi F. Potential role of sorafenib in the treatment of acute myeloid leukemia. Leuk Lymphoma 2009; 49:2246-55. [PMID: 19052971 DOI: 10.1080/10428190802510349] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The identification of aberrant cellular pathways and dysfunctional molecules important in neoplastic transformation has begun to provide us with a number of targets for drug development. It is likely that many of these agents will be incorporated into our existing treatment strategies that include cytotoxic agents. Sorafenib, a multi-kinase inhibitor has been approved in the United States for the treatment of renal cell carcinoma as well as hepatocellular cancer. Its potential role in hematological malignancies, particularly acute myeloid leukemia (AML) is under evaluation. Here we describe the biological pathways in AML that are the potential targets of sorafenib action and discuss the early clinical data with the agent in solid tumors and AML.
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Affiliation(s)
- Shahram Mori
- Department of Leukemia, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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Usher SG, Radford AD, Villiers EJ, Blackwood L. RAS, FLT3, and C-KIT mutations in immunophenotyped canine leukemias. Exp Hematol 2008; 37:65-77. [PMID: 18977066 DOI: 10.1016/j.exphem.2008.09.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 09/08/2008] [Accepted: 09/08/2008] [Indexed: 12/30/2022]
Abstract
OBJECTIVE To determine the frequency of FLT3, C-KIT, and RAS mutations in canine leukemia patients. MATERIALS AND METHODS Ethylenediamine tetra-acetic acid blood samples were recruited from dogs with suspected leukemia, categorized by quantitative and cytological evaluation and immunophenotyping. Flow cytometry was carried out using antibodies against CD3; CD3e; CD4; CD5; CD8; CD11a, b, c, and d; CD14; CD21; CD34; CD45 and 45RA; CD79a; CD90 (THY-1); major histocompatibility complex II; myeloperoxidase; MAC387; and neutrophil-specific antibody. Genomic DNA was extracted from whole blood and analyzed for mutations in N, H, and K-RAS, FLT3, and C-KIT genes by polymerase chain reaction and sequencing. RESULTS Fifty-seven (77.0%) of 74 samples submitted from dogs with suspected leukemia had cytologically and immunophenotypically confirmed leukemia. There were 36 (63.2%) acute leukemias, 16 (28.1%) chronic, 3 (5.3%) prolymphocytic, 1 natural killer cell, and 1 chronic leukemia undergoing blast transformation. N-RAS mis-sense mutations were identified in 14 (25%) dogs with acute myeloid (AML) or lymphoid (ALL) leukemia, and also in one dog in the leukemic phase of lymphoma. Mutations in K-RAS were found in two dogs with AML. There were no H-RAS mutations. FLT3 internal tandem duplications were identified in three dogs with ALL, and a mis-sense mutation was found in one dog with ALL. C-KIT mutations were identified in three dogs with AML. Sixty-one percent of dogs with acute leukemia harbored mutations in N/K-RAS, FLT3, or C-KIT. CONCLUSION RAS, FLT3, and C-KIT mutations, analogous to those found in human leukemia, occur commonly in acute canine leukemia.
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Affiliation(s)
- Suzanne G Usher
- Small Animal Teaching Hospital, University of Liverpool, The Leahurst Campus, Neston, Wirral, UK
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Prognostic relevance of FLT3-TKD mutations in AML: the combination matters—an analysis of 3082 patients. Blood 2008; 111:2527-37. [PMID: 17965322 DOI: 10.1182/blood-2007-05-091215] [Citation(s) in RCA: 285] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We characterized the mutational status of the FLT3 tyrosine kinase domain (FLT3-TLD) in 3082 patients with newly diagnosed AML. FLT3-TKD mutations were detected in 147 of 3082 (4.8%) patients. Similar to the FLT3 juxtamembrane domain mutations (FLT3-LM), there was a high correlation of FLT3-TKD mutations with normal karyotype (88 of 1472; 6.0%). FLT3-TKD mutations were most frequent in the AML FAB subtypes M5b (15 of 114; 13.2%), M3v (6 of 51; 11.8%), and M4 (39 of 484; 8.1%). Similar to FLT3-LM, the FLT3-TKD mutations show elevated peripheral leukocytes compared with FLT3wt AML. FLT3-TKD had a high incidence in cases with NPM1 mutations (23 of 262; 8.8%), CEBPA mutations (6 of 76; 7.9%), and NRAS mutations (6 of 78; 7.7%). FLT3-TKD in combination with FLT3-LM (17 of 594 patients; 2.9%) and KITD816 (1 of 44; 2.3%) was rare. Unlike the FLT3-LM, which are associated with inferior survival, prognosis was not influenced by FLT3-TKD in the total cohort of 1720 cases, where follow-up data were available (97 FLT3-TKD; 1623 FLT3-WT). In t(15;17)/PML-RARA with FLT3-TKD mutations, in FLT3-LM/TKD double-mutated, and in MLL-PTD/TKD double-mutated cases prognosis was unfavorably influenced by FLT3-TKD mutations. In contrast, we found an additional favorable impact of FLT3-TKD on EFS in prognostically favorable AML with NPM1- or CEBPA mutations.
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FLT3mutations in a 10 year consecutive series of 177 childhood acute leukemias and their impact on global gene expression patterns. Genes Chromosomes Cancer 2008; 47:64-70. [DOI: 10.1002/gcc.20508] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Kurmasheva RT, Houghton PJ. Pediatric oncology. Curr Opin Chem Biol 2007; 11:424-32. [PMID: 17652007 PMCID: PMC2265418 DOI: 10.1016/j.cbpa.2007.05.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 05/03/2007] [Accepted: 05/04/2007] [Indexed: 11/24/2022]
Abstract
Intensive use of cytotoxic agents in multimodality therapeutic regimens has resulted in almost 80% five-year disease-free survival and cure in the majority of childhood cancer patients. However, such success has come at the expense of severe acute or delayed toxicities and an increased occurrence of secondary cancers. With an increasing understanding of the genetic changes that underlie transformation in childhood cancer, rational approaches using agents that target these transforming events are being developed. Current and future strategies in developing tumor-selective therapy using inhibitors of signaling pathways dysregulated in leukemias (FLT3, NOTCH1) and solid/brain tumors (ErbB1-4, IGF-IR, PTCH1), and the challenges in developing less toxic, but equally effective treatments in pediatric oncology are presented.
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Affiliation(s)
- Raushan T Kurmasheva
- Department of Molecular Pharmacology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105-2794, United States
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Metzgeroth G, Walz C, Score J, Siebert R, Schnittger S, Haferlach C, Popp H, Haferlach T, Erben P, Mix J, Müller MC, Beneke H, Müller L, Del Valle F, Aulitzky WE, Wittkowsky G, Schmitz N, Schulte C, Müller-Hermelink K, Hodges E, Whittaker SJ, Diecker F, Döhner H, Schuld P, Hehlmann R, Hochhaus A, Cross NCP, Reiter A. Recurrent finding of the FIP1L1-PDGFRA fusion gene in eosinophilia-associated acute myeloid leukemia and lymphoblastic T-cell lymphoma. Leukemia 2007; 21:1183-8. [PMID: 17377585 DOI: 10.1038/sj.leu.2404662] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The FIP1L1-PDGFRA fusion gene has been described in patients with eosinophilia-associated myeloproliferative disorders (Eos-MPD). Here, we report on seven FIP1L1-PDGFRA-positive patients who presented with acute myeloid leukemia (AML, n=5) or lymphoblastic T-cell non-Hodgkin-lymphoma (n=2) in conjunction with AML or Eos-MPD. All patients were male, the median age was 58 years (range, 40-66). AML patients were negative for common mutations of FLT3, NRAS, NPM1, KIT, MLL and JAK2; one patient revealed a splice mutation of RUNX1 exon 7. Patients were treated with imatinib (100 mg, n=5; 400 mg, n=2) either as monotherapy (n=2), as maintenance treatment after intensive chemotherapy (n=3) or in overt relapse 43 and 72 months, respectively, after primary diagnosis and treatment of FIP1L1-PDGFRA-positive disease (n=2). All patients are alive, disease-free and in complete hematologic and complete molecular remission after a median time of 20 months (range, 9-36) on imatinib. The median time to achievement of complete molecular remission was 6 months (range, 1-14). We conclude that all eosinophilia-associated hematological malignancies should be screened for the presence of the FIP1L1-PDGFRA fusion gene as they are excellent candidates for treatment with tyrosine kinase inhibitors even if they present with an aggressive phenotype such as AML.
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Affiliation(s)
- G Metzgeroth
- III. Medizinische Universitätsklinik, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
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19
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Walz C, Curtis C, Schnittger S, Schultheis B, Metzgeroth G, Schoch C, Lengfelder E, Erben P, Müller MC, Haferlach T, Hochhaus A, Hehlmann R, Cross NCP, Reiter A. Transient response to imatinib in a chronic eosinophilic leukemia associated with ins(9;4)(q33;q12q25) and a CDK5RAP2-PDGFRA fusion gene. Genes Chromosomes Cancer 2006; 45:950-6. [PMID: 16845659 DOI: 10.1002/gcc.20359] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Chronic myeloproliferative disorders with rearrangements of the platelet-derived growth factor receptor A (PDGFRA) gene at chromosome band 4q12 have shown excellent responses to targeted therapy with imatinib. Here we report a female patient who presented with advanced phase of a chronic eosinophilic leukemia. Cytogenetic analysis revealed an ins(9;4)(q33;q12q25) in 5 of 21 metaphases. FISH analysis with flanking BAC probes indicated that PDGFRA was disrupted. A novel mRNA in-frame fusion between exon 13 of the CDK5 regulatory subunit associated protein 2 (CDK5RAP2) gene, a 40-bp insert that was partially derived from an inverted sequence stretch of PDGFRA intron 9, and a truncated PDGFRA exon 12 was identified by 5'-RACE-PCR. CDK5RAP2 encodes a protein that is believed to be involved in centrosomal regulation. The predicted CDK5RAP2-PDGFRA protein consists of 1,003 amino acids and retains both tyrosine kinase domains of PDGFRA and several potential dimerization domains of CDK5RAP2. Despite achieving complete cytogenetic and molecular remission on imatinib, the patient relapsed with imatinib-resistant acute myeloid leukemia that was characterized by a normal karyotype, absence of detectable CDK5RAP2-PDGFRA mRNA, and a newly acquired G12D NRAS mutation.
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Affiliation(s)
- Christoph Walz
- III. Medizinische Universitätsklinik, Fakultät für Klinische Medizin Mannheim der Universität Heidelberg, Mannheim, Germany
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20
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Schnittger S, Kohl TM, Haferlach T, Kern W, Hiddemann W, Spiekermann K, Schoch C. KIT-D816 mutations in AML1-ETO-positive AML are associated with impaired event-free and overall survival. Blood 2006; 107:1791-9. [PMID: 16254134 DOI: 10.1182/blood-2005-04-1466] [Citation(s) in RCA: 261] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Mutations in codon D816 of the KIT gene represent a recurrent genetic alteration in acute myeloid leukemia (AML). To clarify the biologic implication of activation loop mutations of the KIT gene, 1940 randomly selected AML patients were analyzed. In total, 33 (1.7%) of 1940 patients were positive for D816 mutations. Of these 33 patients, 8 (24.2%) had a t(8;21), which was significantly higher compared with the subgroup without D816 mutations. Analyses of genetic subgroups showed that KIT-D816 mutations were associated with t(8;21)/AML1-ETO and other rare AML1 translocations. In contrast, other activating mutations like FLT3 and NRAS mutations were very rarely detected in AML1-rearranged leukemia. KIT mutations had an independent negative impact on overall (median 304 vs 1836 days; P = .006) and event-free survival (median 244 vs 744 days; P = .003) in patients with t(8;21) but not in patients with a normal karyotype. The KIT-D816V receptor expressed in Ba/F3 cells was resistant to growth inhibition by the selective PTK inhibitors imatinib and SU5614 but fully sensitive to PKC412. Our findings clearly indicate that activating mutations of receptor tyrosine kinases are associated with distinct genetic subtypes in AML. The KIT-D816 mutations confer a poor prognosis to AML1-ETO-positive AML and should therefore be included in the diagnostic workup. Patients with KIT-D816-positive/AML1-ETO-positive AML might benefit from early intensification of treatment or combination of conventional chemotherapy with KIT PTK inhibitors.
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MESH Headings
- Adult
- Aged
- Amino Acid Substitution
- Cell Line
- Chromosomes, Human, Pair 21/genetics
- Chromosomes, Human, Pair 8/genetics
- Codon/genetics
- Core Binding Factor Alpha 2 Subunit/genetics
- Disease-Free Survival
- Drug Resistance, Neoplasm/drug effects
- Drug Resistance, Neoplasm/genetics
- Female
- Gene Expression/genetics
- Humans
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/mortality
- Male
- Middle Aged
- Oncogene Proteins, Fusion/genetics
- Point Mutation
- Prognosis
- Protein Kinase Inhibitors/pharmacology
- Proto-Oncogene Proteins c-kit/genetics
- RUNX1 Translocation Partner 1 Protein
- Retrospective Studies
- Translocation, Genetic/genetics
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Affiliation(s)
- Susanne Schnittger
- Laboratory of Leukemia Diagnostics and Clinical Cooperative Group Leukemia, Department of Medicine III, University Hospital Grosshadern, Ludwig-Maximilians University, Munich, Germany.
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21
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Schnittger S, Schoch C, Kern W, Mecucci C, Tschulik C, Martelli MF, Haferlach T, Hiddemann W, Falini B. Nucleophosmin gene mutations are predictors of favorable prognosis in acute myelogenous leukemia with a normal karyotype. Blood 2005; 106:3733-9. [PMID: 16076867 DOI: 10.1182/blood-2005-06-2248] [Citation(s) in RCA: 520] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nucleophosmin (NPM1) exon-12 gene mutations are the hallmark of a large acute myelogenous leukemia (AML) subgroup with normal karyotype, but their prognostic value in this AML subset has not yet been determined. We screened 401 AML patients with normal karyotype treated within the German AML Cooperative Group Protocol 99 (AMLCG99) study for NPM1 mutations. Results were related with partial tandem duplications within the MLL gene (MLL-PTD), Fms-like tyrosine kinase 3–length mutations (FLT3-LM), the tyrosine kinase domain of FLT3 (FLT3-TKD), NRAS, KIT, and CEBPA mutations and with clinical characteristics and outcome. NPM1 mutations were detected in 212 (52.9%) of 401 patients. Fourteen mutations, including 8 new variants, were identified. NPM1-mutated cases associated frequently with FLT3 mutations but rarely with other mutations. The NPM1-mutated group had a higher complete remission (CR) rate (70.5% vs 54.7%, P = .003), a trend to a longer overall survival (OS; median 1012 vs 549 days, P = .076), and significantly longer event-free survival (EFS; median 428 vs 336 days; P = .012). The favorable impact of NPM1 mutations on OS and EFS clearly emerged in the large group (264 [66.8%] of 395 cases) of normal-karyotype AML without FLT3-LM. This positive effect was lost in the presence of a concomitant FLT3-LM, since survival of the NPM1+/FLT3-LM+ double positive was similar to NPM1–/FLT3-LM+ cases. In conclusion, this study demonstrates that NPM1+/FLT3-LM– mutations are an independent predictor for a favorable outcome in AML with normal karyotype.
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Affiliation(s)
- Susanne Schnittger
- Department of Internal Medicine III, University Hospital Grosshadern, Ludwig Maximilian's University, Munich, Germany.
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22
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Kern W, Schoch C, Haferlach T, Schnittger S. Monitoring of minimal residual disease in acute myeloid leukemia. Crit Rev Oncol Hematol 2005; 56:283-309. [PMID: 16213150 DOI: 10.1016/j.critrevonc.2004.06.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Revised: 06/24/2004] [Accepted: 06/24/2004] [Indexed: 11/17/2022] Open
Abstract
Monitoring minimal residual disease (MRD) becomes increasingly important in the risk-adapted management of patients with acute myeloid leukemia (AML). The two most sensitive and quantitative methods for MRD detection are multiparameter flow cytometry (MFC) and real-time polymerase chain reaction (QRT-PCR). Fusion gene-specific PCR in AML is based on the RNA level, and thus in contrast to MFC expression levels rather than cell counts are assessed. For both methods independent prognostic values have been shown. The strong power of MFC has been shown mainly in the assessment of early clearance of the malignant clone. MRD levels in AML with fusion genes have the strongest prognostic power after the end of consolidation therapy. In addition, with QRT-PCR highly predictive initial expression levels can be assessed. With both methods early detection of relapse is possible. So far, validated PCR-based MRD was done with fusion genes that are detectable in only 20-25% of all AML MFC is superior since it is applicable for most AML. However, QRT-PCR is still more sensitive in most cases. Thus, it is desirable to establish new molecular markers for PCR-based studies. Large clinical trials will determine the role and place of immunologic and PCR-based monitoring in the prognostic stratification of patients with AML.
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Affiliation(s)
- Wolfgang Kern
- Laboratory for Leukemia Diagnostics, Ludwig-Maximilians-University, University Hospital Grosshadern, Department of Internal Medicine III, 81366 Muenchen, Germany.
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23
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Brown P, Levis M, Shurtleff S, Campana D, Downing J, Small D. FLT3 inhibition selectively kills childhood acute lymphoblastic leukemia cells with high levels of FLT3 expression. Blood 2005; 105:812-20. [PMID: 15374878 DOI: 10.1182/blood-2004-06-2498] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
AbstractFMS-like tyrosine kinase 3 (FLT3) is almost universally expressed in B-precursor childhood acute lymphoblastic leukemia (ALL). Cases of ALL with MLL gene rearrangements and those with high hyperdiploidy (> 50 chromosomes) express the highest levels of FLT3, and activating mutations of FLT3 occur in 18% of MLL-rearranged and 28% of hyperdiploid ALL cases. We determined the antileukemic activity of CEP-701, a potent and selective FLT3 inhibitor, in 8 ALL cell lines and 39 bone marrow samples obtained at diagnosis from infants and children with various subtypes of ALL. CEP-701 induced pronounced apoptotic responses in a higher percentage of samples that expressed high levels of FLT3 (74%, n = 23) compared with samples with low levels of expression (8%, n = 13; P = .0003). Sensitivity to FLT3 inhibition was particularly high in samples with MLL gene rearrangements (82%, n = 11; P = .0005), high hyperdiploidy (100%, n = 5; P = .0007), and/or FLT3 mutations (100%, n = 4; P = .0021). Seven of 7 sensitive samples examined by immunoblotting demonstrated constitutively phosphorylated FLT3 that was potently inhibited by CEP-701, whereas 0 of 6 resistant samples expressed constitutively phosphorylated FLT3. We conclude that the FLT3 inhibitor CEP-701 effectively suppresses FLT3-driven leukemic cell survival. Clinical testing of CEP-701 as a novel molecularly targeted agent for the treatment of childhood ALL is warranted.
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Affiliation(s)
- Patrick Brown
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
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24
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Paietta E, Ferrando AA, Neuberg D, Bennett JM, Racevskis J, Lazarus H, Dewald G, Rowe JM, Wiernik PH, Tallman MS, Look AT. Activating FLT3 mutations in CD117/KIT(+) T-cell acute lymphoblastic leukemias. Blood 2004; 104:558-60. [PMID: 15044257 DOI: 10.1182/blood-2004-01-0168] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Activating FLT3 mutations are the most common genetic aberrations in acute myeloid leukemia (AML), resulting in the constitutive activation of this receptor tyrosine kinase (RTK), but such mutations are rarely found in acute lymphoblastic leukemia (ALL). Here we describe a unique subset of de novo adult T-cell ALL (T-ALL) cases that coexpress CD117/KIT and cytoplasmic CD3 (CD117/KIT(+) ALL). Activating mutations in the FLT3 RTK gene were found in each of 3 CD117/KIT(+) cases that were analyzed, but not in 52 other adult T-ALL samples from the same series that lacked CD117/KIT expression. Our results indicate the need for clinical trials to test the efficacy of drugs that inhibit the FLT3 RTK in this subset of patients with T-ALL.
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Affiliation(s)
- Elisabeth Paietta
- Our Lady of Mercy Cancer Center-Immunology Laboratory, 600 East 233rd St, Bronx, NY 10466, USA.
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25
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Brown P, Small D. FLT3 Inhibitors. Eur J Cancer 2004; 40:707-21, discussion 722-4. [PMID: 15010072 DOI: 10.1016/j.ejca.2003.08.030] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Revised: 08/27/2003] [Accepted: 08/27/2003] [Indexed: 01/01/2023]
Abstract
The area of molecularly-targeted cancer therapeutics is generating tremendous interest and excitement. While clinical investigation of these agents has been largely limited to adults, clinical trials for paediatric cancer patients with many of these agents are now underway. This paper reviews the current status of molecularly-targeted therapies for paediatric malignancies, with special attention given to one class of agents, inhibitors of the FLT3 receptor tyrosine kinase. FLT3 is expressed and activated in many human leukemias, including a significant percentage of pediatric AML and infant and childhood ALL, especially in the setting of MLL gene rearrangement. Activating mutations of FLT3 portend a poor prognosis in pediatric AML. Activated FLT3 can be effectively and selectively targeted by small molecule inhibitors, and these agents have shown promise in early phase clinical trials in adults with AML. Limited preclinical data with FLT3 inhibitors in MLL-rearranged ALL have also been reported. Challenges and future directions for the use of FLT3 inhibitors and other targeted agents in paediatric cancer are discussed.
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Affiliation(s)
- P Brown
- Department of Oncology, Sidney Kimmel Cancer Center at Johns Hopkins, Baltimore, MD 21231-1000, USA
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26
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Gilliland DG. FLT3-activating mutations in acute promyelocytic leukaemia: a rationale for risk-adapted therapy with FLT3 inhibitors. Best Pract Res Clin Haematol 2003; 16:409-17. [PMID: 12935959 DOI: 10.1016/s1521-6926(03)00063-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our understanding of the genetic basis of acute myeloid leukaemias has been enhanced through cloning of recurring chromosomal translocation breakpoints. However, the remarkable observation, more than a decade ago, that all-trans retinoic acid (ATRA) induced remission in patients with t(15;17) acute promyelocytic leukaemia (APL) was a driving force in the subsequent cloning and characterization of the PML-RARalpha fusion that is causally implicated in the pathogenesis of this disease. Major improvements in treatment and outcome of APL patients have been made since that time by incorporating ATRA in conventional chemotherapy but 30% of APL patients still succumb to complications of their disease or their therapy. Recent information that the haematopoietic receptor tyrosine kinase FLT3 is mutated in about 30% of APL patients suggests strategies for further improving treatment and outcome in this subset of APL patients using small-molecule inhibitors of FLT3. The role of FLT3 mutations in APL and other AML will be discussed.
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Affiliation(s)
- D Gary Gilliland
- Howard Hughes Medical Institute, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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27
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Affiliation(s)
- Panagiotis D Kottaridis
- Department of Haematology, Royal Free and University College London Medical School, 98 Chenies Mews, London WC1E 6HX, UK
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28
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van der Velden VHJ, Hochhaus A, Cazzaniga G, Szczepanski T, Gabert J, van Dongen JJM. Detection of minimal residual disease in hematologic malignancies by real-time quantitative PCR: principles, approaches, and laboratory aspects. Leukemia 2003; 17:1013-34. [PMID: 12764363 DOI: 10.1038/sj.leu.2402922] [Citation(s) in RCA: 411] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Detection of minimal residual disease (MRD) has prognostic value in many hematologic malignancies, including acute lymphoblastic leukemia, acute myeloid leukemia, chronic myeloid leukemia, non-Hodgkin's lymphoma, and multiple myeloma. Quantitative MRD data can be obtained with real-time quantitative PCR (RQ-PCR) analysis of immunoglobulin and T-cell receptor gene rearrangements, breakpoint fusion regions of chromosome aberrations, fusion-gene transcripts, aberrant genes, or aberrantly expressed genes, their application being dependent on the type of disease. RQ-PCR analysis can be performed with SYBR Green I, hydrolysis (TaqMan) probes, or hybridization (LightCycler) probes, as detection system in several RQ-PCR instruments. Dependent on the type of MRD-PCR target, different types of oligonucleotides can be used for specific detection, such as an allele-specific oligonucleotide (ASO) probe, an ASO forward primer, an ASO reverse primer, or germline probe and primers. To assess the quantity and quality of the RNA/DNA, one or more control genes must be included. Finally, the interpretation of RQ-PCR MRD data needs standardized criteria and reporting of MRD data needs international uniformity. Several European networks have now been established and common guidelines for data analysis and for reporting of MRD data are being developed. These networks also include standardization of technology as well as regular quality control rounds, both being essential for the introduction of RQ-PCR-based MRD detection in multicenter clinical treatment protocols.
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Affiliation(s)
- V H J van der Velden
- Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Dr Molewaterplein 50, Rotterdam 3015 GE, The Netherlands
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29
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Abstract
Human leukemias are typified by acquired recurring chromosomal translocations. Cloning of these translocation breakpoints has provided important insights into pathogenesis of disease as well as novel therapeutic approaches. Chronic myelogenous leukemias (CML) are caused by constitutively activated tyrosine kinases, such as BCR/ABL, that confer a proliferative and survival advantage to hematopoietic progenitors but do not affect differentiation. These activated kinases are validated targets for therapy with selective tyrosine kinase inhibitors, a paradigm that may have broad applications in treatment of hematologic malignancies as well as solid tumors. Chromosomal translocations in acute myeloid leukemias (AML) most often result in loss-of-function mutations in transcription factors that are required for normal hematopoietic development. These latter mutations, however, are not sufficient to cause AML. The available evidence indicates that activating mutations in the hematopoietic tyrosine kinases FLT3 and c-KIT, and in N-RAS and K-RAS, confer proliferative advantage to hematopoietic progenitors and cooperate with loss-of-function mutations in hematopoietic transcription factors to cause an acute leukemia phenotype characterized by proliferation and impaired differentiation. The data supporting this hypothesis and the clinical and therapeutic implications of these observations are reviewed.
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Affiliation(s)
- Louise M Kelly
- Howard Hughes Medical Institute, Brigham and Women's Hospital, Harvard Institutes of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA.
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30
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Shih LY, Huang CF, Wu JH, Lin TL, Dunn P, Wang PN, Kuo MC, Lai CL, Hsu HC. Internal tandem duplication of FLT3 in relapsed acute myeloid leukemia: a comparative analysis of bone marrow samples from 108 adult patients at diagnosis and relapse. Blood 2002; 100:2387-92. [PMID: 12239146 DOI: 10.1182/blood-2002-01-0195] [Citation(s) in RCA: 235] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Analysis of internal tandem duplications of FLT3 (FLT3/ITD) was performed on bone marrow samples obtained at diagnosis and relapse from 108 adult patients with de novo acute myeloid leukemia (AML) to determine the role of this mutation in leukemic relapse. Eighty-three patients had wild-type FLT3 at both diagnosis and relapse, 16 had FLT3/ITD at both stages, whereas 8 had acquired the mutation and 1 had lost it at relapse. Using Genescan analysis, we found that FLT3/ITD levels at first relapse were significantly higher than those at diagnosis (mean +/- SE, 40.5% +/- 4.8% versus 17.9% +/- 3.6%, P <.001). The increase in mutation levels at relapse as compared with diagnosis did not correlate with the difference in blast cell percentages at both stages (P =.777). A hemizygous deletion of wild-type FLT3 was found in 4 patients at relapse compared to none at diagnosis. Nine of the 11 patients carrying a single mutation at diagnosis relapsed with an identical mutation. All 6 patients with more than one FLT3/ITD mutation at diagnosis showed changes in mutation patterns and levels at first relapse; however, each patient retained at least one mutation in the relapse sample. The changes of mutation patterns had implications for the monitoring of minimal residual disease. Our results suggest that FLT3/ITD may contribute as the initial transforming event in AML, and relapse can reflect the selection and outgrowth of a mutant clone or evolution of a new clone harboring this mutation.
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Affiliation(s)
- Lee-Yung Shih
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, and Chang Gung University, Taipei, Taiwan.
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31
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Hovland R, Gjertsen BT, Bruserud O. Acute myelogenous leukemia with internal tandem duplication of the Flt3 gene appearing or altering at the time of relapse: a report of two cases. Leuk Lymphoma 2002; 43:2027-9. [PMID: 12481903 DOI: 10.1080/1042819021000015989] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Detection of Flt3-internal tandem duplication (ITD) in acute myelogenous leukemia (AML) blasts at the time of diagnosis is associated with an increased risk of leukemia relapse after chemotherapy. In the present report, we describe two patients with Flt3-abnormalities that were only detectable at the time of relapse. One of the patients had an ITD at the time of diagnosis (duplicated region 41-133 numbered from the start of exon 14 plus CGG insertion), but at the time of relapse a new abnormality (duplicated region 70-230 plus insertion GGGGAGT) was detected as the only Flt3-abnormality. The second patient showed no Flt3-ITD at the time of diagnosis, but ITD was detected at the time of relapse (duplicated region 12-96, no insertion). Our observations of independent Flt3-ITD and the detection of new Flt3-abnormalities at the time of relapse suggest that (i) Flt3-gene abnormalities may be even more important in the pathogenesis of chemotherapy-resistant AML than suggested from previous studies of newly diagnosed AML, and (ii) monitoring of minimal residual disease by using patient-specific real-time polymerase chain reaction assays for Flt3-abnormalities may not be reliable.
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Affiliation(s)
- Randi Hovland
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital and University of Bergen, Bergen, Norway
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32
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Affiliation(s)
- John T Reilly
- Molecular Haematology Unit, Division of Molecular and Genetic Medicine, Royal Hallamshire Hospital, Sheffield, UK.
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