201
|
Pardanani A, Reeder T, Porrata LF, Li CY, Tazelaar HD, Baxter EJ, Witzig TE, Cross NCP, Tefferi A. Imatinib therapy for hypereosinophilic syndrome and other eosinophilic disorders. Blood 2003; 101:3391-7. [PMID: 12506022 DOI: 10.1182/blood-2002-10-3103] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Imatinib mesylate (Gleevec), a small molecule inhibitor of abl, kit, and platelet-derived growth factor receptor (PDGFR) tyrosine kinases, has been reported to be effective in the treatment of hypereosinophilic syndrome (HES) and a rare eosinophilia-associated chronic myeloid disorder (eos-CMD) characterized by the t(5;12)(q33;p13) cytogenetic abnormality. In the current study, we sought to confirm the preliminary observations in HES as well as evaluate the therapeutic value of imatinib in eos-CMD that is not associated with t(5;12)(q33;p13). Five patients with HES (all men, median age = 46 years) and 2 with eos-CMD (both men, aged 45 and 58 years) were treated with imatinib at a starting dose of 100 to 400 mg/day. Cytogenetic studies showed no evidence of either the bcr-abl translocation or t(5;12)(q33;p13) in any patient. Screening of exons encoding the intracellular catalytic domains and extracellular ligand binding domains of PDGFR beta (exons 2-23) and c-kit (exons 1-21) in 6 patients demonstrated mostly previously known polymorphisms. At a median follow-up of 17 weeks (range, 10-33 weeks), 2 patients with HES and 1 with eos-CMD have achieved complete clinical remission and 1 additional patient with HES has achieved a partial remission. In contrast to previous observations, all 4 responding patients had elevated serum interleukin-5 levels. Although the drug was well tolerated in most patients, a previously unrecognized treatment toxicity of acute left ventricular dysfunction occurred in a responding patient with HES within the first week of treatment. Myocardial biopsy revealed eosinophilic infiltration and degranulation, and the cardiogenic shock was reversed with the prompt institution of corticosteroid therapy.
Collapse
|
202
|
Cools J, DeAngelo DJ, Gotlib J, Stover EH, Legare RD, Cortes J, Kutok J, Clark J, Galinsky I, Griffin JD, Cross NCP, Tefferi A, Malone J, Alam R, Schrier SL, Schmid J, Rose M, Vandenberghe P, Verhoef G, Boogaerts M, Wlodarska I, Kantarjian H, Marynen P, Coutre SE, Stone R, Gilliland DG. A tyrosine kinase created by fusion of the PDGFRA and FIP1L1 genes as a therapeutic target of imatinib in idiopathic hypereosinophilic syndrome. N Engl J Med 2003; 348:1201-14. [PMID: 12660384 DOI: 10.1056/nejmoa025217] [Citation(s) in RCA: 1157] [Impact Index Per Article: 55.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Idiopathic hypereosinophilic syndrome involves a prolonged state of eosinophilia associated with organ dysfunction. It is of unknown cause. Recent reports of responses to imatinib in patients with the syndrome suggested that an activated kinase such as ABL, platelet-derived growth factor receptor (PDGFR), or KIT, all of which are inhibited by imatinib, might be the cause. METHODS We treated 11 patients with the hypereosinophilic syndrome with imatinib and identified the molecular basis for the response. RESULTS Nine of the 11 patients treated with imatinib had responses lasting more than three months in which the eosinophil count returned to normal. One such patient had a complex chromosomal abnormality, leading to the identification of a fusion of the Fip1-like 1 (FIP1L1) gene to the PDGFRalpha (PDGFRA) gene generated by an interstitial deletion on chromosome 4q12. FIP1L1-PDGFRalpha is a constitutively activated tyrosine kinase that transforms hematopoietic cells and is inhibited by imatinib (50 percent inhibitory concentration, 3.2 nM). The FIP1L1-PDGFRA fusion gene was subsequently detected in 9 of 16 patients with the syndrome and in 5 of the 9 patients with responses to imatinib that lasted more than three months. Relapse in one patient correlated with the appearance of a T674I mutation in PDGFRA that confers resistance to imatinib. CONCLUSIONS The hypereosinophilic syndrome may result from a novel fusion tyrosine kinase - FIP1L1-PDGFRalpha - that is a consequence of an interstitial chromosomal deletion. The acquisition of a T674I resistance mutation at the time of relapse demonstrates that FIP1L1-PDGFRalpha is the target of imatinib. Our data indicate that the deletion of genetic material may result in gain-of-function fusion proteins.
Collapse
|
203
|
Deguchi K, Ayton PM, Carapeti M, Kutok JL, Snyder CS, Williams IR, Cross NCP, Glass CK, Cleary ML, Gilliland DG. MOZ-TIF2-induced acute myeloid leukemia requires the MOZ nucleosome binding motif and TIF2-mediated recruitment of CBP. Cancer Cell 2003; 3:259-71. [PMID: 12676584 DOI: 10.1016/s1535-6108(03)00051-5] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The MOZ-TIF2 fusion is associated with acute myeloid leukemia (AML) with inv(8)(p11q13). MOZ is a MYST family histone acetyltransferase (HAT), whereas TIF2 is a nuclear receptor coactivator that associates with CREB binding protein (CBP). Here we demonstrate that MOZ-TIF2 has transforming properties in vitro and causes AML in a murine bone marrow transplant assay. The C2HC nucleosome recognition motif of MOZ is essential for transformation, whereas MOZ HAT activity is dispensable. However, MOZ-TIF2 interaction with CBP through the TIF2 CBP interaction domain (CID) is essential for transformation. These results indicate that nucleosomal targeting by MOZ and recruitment of CBP by TIF2 are critical requirements for MOZ-TIF2 transformation and indicate that MOZ gain of function contributes to leukemogenesis.
Collapse
|
204
|
Reiter A, Saussele S, Grimwade D, Wiemels JL, Segal MR, Lafage-Pochitaloff M, Walz C, Weisser A, Hochhaus A, Willer A, Reichert A, Büchner T, Lengfelder E, Hehlmann R, Cross NCP. Genomic anatomy of the specific reciprocal translocation t(15;17) in acute promyelocytic leukemia. Genes Chromosomes Cancer 2003; 36:175-88. [PMID: 12508246 DOI: 10.1002/gcc.10154] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The genomic breakpoints in the t(15;17)(q22;q21), associated with acute promyelocytic leukemia (APL), are known to occur within three different PML breakpoint cluster regions (bcr) on chromosome 15 and within RARA intron 2 on chromosome 17; however, the precise mechanism by which this translocation arises is unclear. To clarify this mechanism, we (i). assembled the sequence of RARA intron 2, (ii). amplified and sequenced the genomic PML-RARA junction sequences from 37 APL patients, and (iii). amplified and sequenced the reverse RARA-PML genomic fusion in 29 of these cases. Three significant breakpoint microclusters within RARA intron 2 were identified, suggesting that sequence-associated or structural factors play a role in the formation of the t(15;17). There was no evidence that the location of a breakpoint in PML had any relationship to the location of the corresponding breakpoint in RARA. Although some sequence motifs previously implicated in illegitimate recombinations were found in the microcluster regions, these associations were not significant. Comparison of forward and reverse genomic junctions revealed microhomologies, deletions, and/or duplications of either gene in all but one case, in which a complex rearrangement with inversion of the PML-derived sequence was found. These findings are consistent with the hypothesis that the t(15;17) occurs by nonhomologous recombination of DNA after processing of the double-strand breaks by a dysfunctional DNA damage-repair mechanism.
Collapse
MESH Headings
- Chromosome Breakage/genetics
- Chromosome Mapping
- Chromosomes, Human, Pair 15/genetics
- Chromosomes, Human, Pair 17/genetics
- Cloning, Molecular
- Cytogenetic Analysis/methods
- Humans
- Introns/genetics
- Leukemia, Promyelocytic, Acute/genetics
- Mutagenesis, Insertional/genetics
- Neoplasm Proteins/genetics
- Oncogene Proteins, Fusion/genetics
- Receptors, Retinoic Acid/genetics
- Retinoic Acid Receptor alpha
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
- Translocation, Genetic/genetics
Collapse
|
205
|
Baxter EJ, Kulkarni S, Vizmanos JL, Jaju R, Martinelli G, Testoni N, Hughes G, Salamanchuk Z, Calasanz MJ, Lahortiga I, Pocock CF, Dang R, Fidler C, Wainscoat JS, Boultwood J, Cross NCP. Novel translocations that disrupt the platelet-derived growth factor receptor beta (PDGFRB) gene in BCR-ABL-negative chronic myeloproliferative disorders. Br J Haematol 2003; 120:251-6. [PMID: 12542482 DOI: 10.1046/j.1365-2141.2003.04051.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The BCR-ABL-negative chronic myeloproliferative disorders (CMPD) and myelodysplastic/myeloproliferative diseases (MDS/MPD) are a spectrum of related conditions for which the molecular pathogenesis is poorly understood. Translocations that disrupt and constitutively activate the platelet-derived growth factor receptor beta(PDGFRB) gene at chromosome band 5q33 have been described in some patients, the most common being the t(5;12)(q33;p13). An accurate molecular diagnosis of PDGFRB-rearranged patients has become increasingly important since recent data have indicated that they respond very well to imatinib mesylate therapy. In this study, we have tested nine patients with a CMPD or MDS/MPD and a translocation involving 5q31-33 for disruption of PDGFRB by two-colour fluorescence in situ hybridization (FISH) using differentially labelled, closely flanking probes. Normal control interphase cells gave a false positive rate of 3% (signals more than one signal width apart). Six patients showed a pattern of one fused signal (from the normal allele) and one pair of signals separated by more than one signal width in > 85% of interphase cells, indicating that PDGFRB was disrupted. These individuals had a t(1;5)(q21;q33), t(1;5)(q22;q31), t(1;3;5)(p36;p21;q33), t(2;12;5)(q37;q22;q33), t(3;5) (p21;q31) and t(5;14)(q33;q24) respectively. The remaining three patients with a t(1;5)(q21;q31), t(2;5)(p21;q33) and t(5;6)(q33;q24-25) showed a normal pattern of hybridization, with > or = 97% interphase cells with two fusion signals. We conclude that two-colour FISH is useful to determine the presence of a PDGFRB rearrangement, although, as we have shown previously, this technique may not detect subtle complex translocations at this locus. Our data indicate that several PDGFRB partner genes remain to be characterized.
Collapse
MESH Headings
- Chromosomes, Human, Pair 1
- Chromosomes, Human, Pair 5
- Chromosomes, Human, Pair 9
- Eosinophilia/genetics
- Female
- Fusion Proteins, bcr-abl
- Humans
- In Situ Hybridization, Fluorescence
- Male
- Myeloproliferative Disorders/genetics
- Polymerase Chain Reaction/methods
- Receptor, Platelet-Derived Growth Factor beta/genetics
- Sensitivity and Specificity
- Translocation, Genetic
Collapse
|
206
|
Hochhaus A, Kreil S, Corbin AS, La Rosée P, Müller MC, Lahaye T, Hanfstein B, Schoch C, Cross NCP, Berger U, Gschaidmeier H, Druker BJ, Hehlmann R. Molecular and chromosomal mechanisms of resistance to imatinib (STI571) therapy. Leukemia 2002; 16:2190-6. [PMID: 12399961 DOI: 10.1038/sj.leu.2402741] [Citation(s) in RCA: 622] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2002] [Accepted: 07/23/2002] [Indexed: 11/08/2022]
Abstract
Selective inhibition of the BCR-ABL tyrosine kinase by imatinib (STI571, Glivec/Gleevec) is a promising new therapeutic strategy in patients with chronic myelogenous leukemia (CML). Despite significant hematologic and cytogenetic responses, resistance occurs, particularly in patients with advanced disease. We sought to determine the underlying mechanisms. Sixty-six patients with CML in myeloid blast crisis (n = 33), lymphoid blast crisis (n = 2), accelerated phase (n = 16), chronic phase (n = 13), and BCR-ABL-positive acute lymphoblastic leukemia (n = 2) resistant to imatinib were investigated. Median duration of imatinib therapy was 148 days (range 6-882). Patients were evaluated for genomic amplification of BCR-ABL, overexpression of BCR-ABL transcripts, clonal karyotypic evolution, and mutations of the imatinib binding site in the BCR-ABL tyrosine kinase domain. Results were as follows: (1) Median levels of BCR-ABL transcripts, were not significantly changed at the time of resistance but 7/55 patients showed a >10-fold increase in BCR-ABL levels; (2) genomic amplification of BCR-ABL was found in 2/32 patients evaluated by fluorescence in situ hybridization; (3) additional chromosomal aberrations were observed in 19/36 patients; (4) point mutations of the ABL tyrosine kinase domain resulting in reactivation of the BCR-ABL tyrosine kinase were detected in 23/66 patients. In conclusion, although the heterogeneous development of imatinib resistance is challenging, the fact that BCR-ABL is active in many resistant patients suggests that the chimeric oncoprotein remains a good therapeutic target. However, patients with clonal evolution are more likely to have BCR-ABL-independent mechanisms of resistance. The observations warrant trials combining imatinib with other agents.
Collapse
MESH Headings
- Antineoplastic Agents/therapeutic use
- Benzamides
- Chromosome Aberrations/drug effects
- DNA Mutational Analysis
- DNA Primers/chemistry
- DNA, Neoplasm/metabolism
- Drug Resistance, Neoplasm/genetics
- Enzyme Inhibitors/therapeutic use
- Fusion Proteins, bcr-abl/genetics
- Genes, abl/genetics
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Mutation
- Neoplasm Recurrence, Local/genetics
- Piperazines/therapeutic use
- Polymerase Chain Reaction
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/genetics
- Pyrimidines/therapeutic use
- Treatment Outcome
Collapse
|
207
|
Apperley JF, Gardembas M, Melo JV, Russell-Jones R, Bain BJ, Baxter EJ, Chase A, Chessells JM, Colombat M, Dearden CE, Dimitrijevic S, Mahon FX, Marin D, Nikolova Z, Olavarria E, Silberman S, Schultheis B, Cross NCP, Goldman JM. Response to imatinib mesylate in patients with chronic myeloproliferative diseases with rearrangements of the platelet-derived growth factor receptor beta. N Engl J Med 2002; 347:481-7. [PMID: 12181402 DOI: 10.1056/nejmoa020150] [Citation(s) in RCA: 506] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND A small proportion of patients with chronic myeloproliferative diseases have constitutive activation of the gene for platelet-derived growth factor receptor beta (PDGFRB), which encodes a receptor tyrosine kinase. The gene is located on chromosome 5q33, and the activation is usually caused by a t(5;12)(q33;p13) translocation associated with an ETV6-PDGFRB fusion gene. The tyrosine kinase inhibitor imatinib mesylate specifically inhibits ABL, PDGFR, and KIT kinases and has impressive clinical efficacy in BCR-ABL-positive chronic myeloid leukemia. METHODS We treated four patients who had chronic myeloproliferative diseases and chromosomal translocations involving 5q33 with imatinib mesylate (400 mg daily). Three of the four patients presented with leukocytosis and eosinophilia; their leukemia cells carried the ETV6-PDGFRB fusion gene. The fourth patient had leukocytosis, eosinophilia, and a t(5;12) translocation involving PDGFRB and an unknown partner gene; he also had extensive raised, ulcerated skin lesions that had been present for a long time. RESULTS In all four patients, a normal blood count was achieved within four weeks after treatment began. In the patient with skin disease, the lesions began to resolve shortly after treatment began. The t(5;12) translocation was undetectable by 12 weeks in three patients and by 36 weeks in the fourth patient. In the three patients with the ETV6-PDGFRB fusion gene, the transcript level decreased, and in one patient, it became undetectable by 36 weeks. All responses were durable at 9 to 12 months of follow-up. CONCLUSIONS Imatinib mesylate induces durable responses in patients with chronic myeloproliferative diseases associated with activation of PDGFRB.
Collapse
|
208
|
Cross NCP, Reiter A. Tyrosine kinase fusion genes in chronic myeloproliferative diseases. Leukemia 2002; 16:1207-12. [PMID: 12094244 DOI: 10.1038/sj.leu.2402556] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2002] [Accepted: 02/14/2002] [Indexed: 11/08/2022]
Abstract
With the exception of chronic myeloid leukemia (CML), chronic myeloproliferative disorders (CMPDs) are a heterogeneous spectrum of conditions for which the molecular pathogenesis is not well understood. Most cases have a normal or aneuploid karyotype, but a minority present with a reciprocal translocation that disrupts specific tyrosine kinase genes, most commonly PDGFRB or FGFR1. These translocations result in the production of constitutively active tyrosine kinase fusion proteins that deregulate hemopoiesis in a manner analogous to BCR-ABL. With the advent of targeted signal transduction therapy, an accurate clinical and molecular diagnosis of CMPDs has become increasingly important. Currently, patients with PDGFRB or ABL fusion genes are candidates for treatment with Imatinib (STI571), but it is likely that alternative strategies will be necessary for the treatment of most other patients.
Collapse
|
209
|
Granjo E, Lima M, Lopes JM, Dória S, Orfão A, Ying S, Barata LT, Miranda M, Cross NCP, Bain BJ. Chronic eosinophilic leukaemia presenting with erythroderma, mild eosinophilia and hyper-IgE: clinical, immunological and cytogenetic features and therapeutic approach. A case report. Acta Haematol 2002; 107:108-12. [PMID: 11919392 DOI: 10.1159/000046640] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A 23-year-old, white male metallurgist presented with pruritic erythematous maculo-papules over the trunk and upper limbs and 6 months later developed erythroderma, eosinophilia and multi-organ dysfunction. A diagnosis of chronic eosinophilic leukaemia was made on the basis of myeloproliferative involvement of both peripheral blood and bone marrow, associated with eosinophilic differentiation and a t(5;12)(q33;p13) translocation. The initial therapeutic approach was interferon alfa-2b plus cytosine arabinoside, for 13 months, followed by hydroxyurea plus vincristine. There was improvement of skin lesions, disappearance of eosinophilia and decrease of serum immunoglobulin E, towards normal values.
Collapse
|
210
|
Steer EJ, Cross NCP. Myeloproliferative disorders with translocations of chromosome 5q31-35: role of the platelet-derived growth factor receptor Beta. Acta Haematol 2002; 107:113-22. [PMID: 11919393 DOI: 10.1159/000046641] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Acquired reciprocal chromosomal translocations that involve chromosome bands 5q31-33 are associated with a significant minority of patients with BCR-ABL-negative chronic myeloid leukemias. The most common abnormality is the t(5;12)(q33;p13), which fuses the ETV6/TEL gene to the platelet-derived growth factor receptor-beta (PDGFRB), a receptor tyrosine kinase that maps to 5q33. PDGFRB is disrupted by other translocations and to date four additional partner genes (H4, HIP1, CEV14 and Rab5) have been reported. Clinically, most patients present with a myeloproliferative disorder (MPD) with eosinophilia, eosinophilic leukemia or chronic myelomonocytic leukemia and thus fall into the broader category of myeloproliferative disorders/myelodysplastic syndromes (MPD/MDS). With the advent of targeted signal transduction therapy, patients with rearrangement of PDGFRB might be better classified as a distinct subgroup of MPD/MDS.
Collapse
|
211
|
Macdonald D, Reiter A, Cross NCP. The 8p11 myeloproliferative syndrome: a distinct clinical entity caused by constitutive activation of FGFR1. Acta Haematol 2002; 107:101-7. [PMID: 11919391 DOI: 10.1159/000046639] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Several recurrent translocations that involve chromosome band 8p11 have been described in myeloid malignancies. These translocations target two distinct genes: (1) FGFR1, a receptor tyrosine kinase for fibroblast growth factors, and (2) MOZ, a putative histone acetyltransferase whose precise function remains to be defined. Disruption of FGFR1 is associated with a disease entity known as the 8p11 myeloproliferative syndrome (EMS)/stem cell leukemia-lymphoma syndrome, a chronic myeloproliferative disorder that frequently presents with eosinophilia and associated T-cell lymphoblastic lymphoma. The disease is aggressive and rapidly transforms to acute leukaemia, usually of myeloid phenotype. Currently, only allogeneic stem cell transplantation appears to be effective in eradicating or suppressing the malignant clone. To date, four gene fusions associated with distinct translocations have been described in EMS: the t(8;13)(p11;q12), t(8;9)(p11;q33), t(6;8)(q27;p11) and t(8;22)(p11q22) fuse ZNF198, CEP110, FOP and BCR, respectively, to FGFR1. The resulting fusion proteins have constitutive tyrosine kinase activity and activate multiple signal transduction pathways. These pathways and the fusion proteins are attractive targets for targeted signal transduction therapy.
Collapse
|
212
|
Baxter EJ, Hochhaus A, Bolufer P, Reiter A, Fernandez JM, Senent L, Cervera J, Moscardo F, Sanz MA, Cross NCP. The t(4;22)(q12;q11) in atypical chronic myeloid leukaemia fuses BCR to PDGFRA. Hum Mol Genet 2002; 11:1391-7. [PMID: 12023981 DOI: 10.1093/hmg/11.12.1391] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chronic myeloid leukaemia (CML) is characterized by the presence of the BCR-ABL fusion gene, usually in association with the t(9;22)(q34;q11) translocation. We report here the identification and cloning of a rare variant translocation, t(4;22)(q12;q11), in two patients with a CML-like myeloproliferative disease (MPD). RT-PCR indicated that both patients were negative for BCR-ABL, but FISH analysis suggested that the BCR gene was rearranged. Since other translocations in MPDs frequently involve tyrosine kinases, we designed a multiplex PCR to search for mRNA fusions between BCR and three potential partner genes at 4q12: KIT, KDR and PDGFRA. An unusual inframe BCR-PDGFRA fusion mRNA was identified in both patients, with either BCR exon 7 or exon 12 fused to short BCR intron-derived sequences, which were in turn fused to part of PDGFRA exon 12. Sequencing of the genomic breakpoint junctions showed that the chromosome 22 breakpoints fell in BCR introns whereas the chromosome 4 breakpoints were within PDGFRA exon 12. This is the first report of a fusion gene that involves PDGFRA. Our findings indicate that apparently simple cytogenetic variants of t(9;22) do not always mask a cryptic BCR-ABL fusion, even when found in association with clinical and haematological indications of CML.
Collapse
MESH Headings
- Adult
- Child, Preschool
- Chromosomes, Human, Pair 22
- Chromosomes, Human, Pair 4
- Fusion Proteins, bcr-abl/genetics
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Male
- RNA, Messenger
- Receptors, Platelet-Derived Growth Factor/genetics
- Sequence Analysis, RNA
- Translocation, Genetic
Collapse
|
213
|
Billio A, Steer EJ, Pianezze G, Svaldi M, Casin M, Amato B, Coser P, Cross NCP. A further case of acute myeloid leukaemia with inv(8)(p11q13) and MOZ-TIF2 fusion. Haematologica 2002; 87:ECR15. [PMID: 12010678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
|
214
|
Aguiar RCT, Chase A, Oscier DG, Carapeti M, Goldman JM, Cross NCP. Characterization of a t(10;12)(q24;p13) in a case of CML in transformation. Genes Chromosomes Cancer 1997. [DOI: 10.1002/(sici)1098-2264(199712)20:4<408::aid-gcc13>3.0.co;2-i] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|