Chronic myeloproliferative disorder with t(8;22)(p11;q11) can mime clonal cytogenetic evolution of authentic chronic myelogeneous leukemia

Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions: reevaluation of the defining characteristics in a registry-based cohort

In a registry-based analysis of 135 patients with "myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions" (MLN-TK; FIP1L1::PDGFRA, n = 78; PDGFRB, diverse fusions, n = 26; FGFR1, diverse, n = 9; JAK2, diverse, n = 11; ETV6::ABL1, n = 11), we sought to evaluate the disease-defining characteristics. In 81/135 (60%) evaluable patients, hypereosinophilia (>1.5 × 109/l) was observed in 40/44 (91%) FIP1L1::PDGFRA and 7/7 (100%) ETV6::ABL1 positive patients but only in 13/30 (43%) patients with PDGFRB, FGFR1, and JAK2 fusion genes while 9/30 (30%) patients had no eosinophilia. Monocytosis >1 × 109/l was identified in 27/81 (33%) patients, most frequently in association with hypereosinophilia (23/27, 85%). Overall, a blast phase (BP) was diagnosed in 38/135 (28%) patients (myeloid, 61%; lymphoid, 39%), which was at extramedullary sites in 18 (47%) patients. The comparison between patients with PDGFRA/PDGFRB vs. FGFR1, JAK2, and ETV6::ABL1 fusion genes revealed a similar occurrence of primary BP (17/104, 16% vs. 8/31 26%, p = 0.32), a lower frequency (5/87, 6% vs. 8/23, 35%, p = 0.003) of and a later progression (median 87 vs. 19 months, p = 0.053) into secondary BP, and a better overall survival from diagnosis of BP (17.1 vs. 1.7 years, p < 0.0008). We conclude that hypereosinophilia with or without monocytosis and various phenotypes of BP occur at variable frequencies in MLN-TK.

Synergetic effect of Azacitidine and Sorafenib in treatment of a case of myeloid neoplasm with sole chromosomal abnormality t(8;22)(p11.2;q11.2)/BCR-FGFR1 rearrangement

The sole t(8;22)(p11.2;q11.2)/BCR- FGFR1 chromosomal abnormality formerly known as aCML is an extremely rare disease entity with a history of rapid progression. Though patients resemble phenotypically chronic myeloid leukemia, the treatment of patients with sole BCR-FGFR1 rearrangement are still challenging for clinicians due to rapid progressive nature and unavailability of uniform treatment guidelines. In present case study, we describe a case of myeloid neoplasm with sole chromosomal abnormality of t(8;22)(p11.2;q11.2)/BCR-FGFR1 rearrangement which is successfully managed by Sorafenib with Azacitidine. Hence our case report suggests that combination of Sorafenib and Azacitidine treatment is effective in sole BCR-FGFR1 rearrangement, however this combination therapy should be studied in large clinical trials.

A case of a patient characterized by t(8;22)(p11;q11) and BCR/FGFR1 fusion gene, who was successfully treated with haploidentical hematopoietic stem cell transplantation

Objective: The 8p11 myeloproliferative syndrome [EMS] is a rare myeloproliferative disorder which usually develops rapidly with chromosomal translocation of the fibroblast growth factor receptor 1 gene. The gene has 15 fusion partners, including the breakpoint cluster region (BCR) gene on chromosome 22. Of all the tests available, chromosome karyotype determination is the most important for the diagnosis of EMS. Here, we describe one case of a patient characterized by marked increase of white blood cells and thrombocytopenia and diagnosed as EMS with t(8;22)(p11;q11) by chromosome karyotype.Methods: 28-year-old man was referred to our hospital. He had a onemonth history of intermittent coughing and a small amount of expectoration after catching a cold. As an outpatient, his complete blood count showed: WBC was 130.04 × 10⁹/L with 80.20% granulocytes.Hematologic investigations, bone marrow analysis and genomic DNA sequencing studies were performed.Results: Despite additional chromosomal abnormalities,the patient progressed rapidly with a B blast cell clone in one month. After diagnosis inthree months, the patient underwent the haplo-identical BMT of his brother, followed up for three years, and had a high rate of survival.Conclusions: Our report provides a definite conceptual framework for a better understanding of the characteristics of The 8p11 myeloproliferative syndrome [EMS].

Functional characterization of two rare BCR-FGFR1+ leukemias

8p11 myeloproliferative syndrome (EMS) represents a unique World Health Organization (WHO)-classified hematologic malignancy defined by translocations of the FGFR1 receptor. The syndrome is a myeloproliferative neoplasm characterized by eosinophilia and lymphadenopathy, with risk of progression to either acute myeloid leukemia (AML) or T- or B-lymphoblastic lymphoma/leukemia. Within the EMS subtype, translocations between breakpoint cluster region (BCR) and fibroblast growth factor receptor 1 (FGFR1) have been shown to produce a dominant fusion protein that is notoriously resistant to tyrosine kinase inhibitors (TKIs). Here, we report two cases of BCR–FGFR1⁺ EMS identified via RNA sequencing (RNA-seq) and confirmed by fluorescence in situ hybridization (FISH). Sanger sequencing revealed that both cases harbored the exact same breakpoint. In the first case, the patient presented with AML-like disease, and in the second, the patient progressed to B-cell acute lymphoblastic leukemia (B-ALL). Additionally, we observed that that primary leukemia cells from Case 1 demonstrated sensitivity to the tyrosine kinase inhibitors ponatinib and dovitinib that can target FGFR1 kinase activity, whereas primary cells from Case 2 were resistant to both drugs. Taken together, these results suggest that some but not all BCR–FGFR1 fusion positive leukemias may respond to TKIs that target FGFR1 kinase activity.

A Case of Myeloproliferative Neoplasm with BCR-FGFR1 Rearrangement: Favorable Outcome after Haploidentical Allogeneic Transplantation

Hematopoietic myeloproliferative neoplasms with FGFR1 rearrangement result in the 8p11 myeloproliferative syndrome that in the current Word Health Organization classification is designated as “myeloid and lymphoid neoplasm with FGFR1 abnormalities.” We report the case of a 66-year-old man who had clinical features that resembled chronic myeloid leukaemia (CML), but bone marrow cytogenetic and fluorescent in situ hybridization (FISH) studies showed t(8;22)(p11;q11) and BCR-FGFR1 fusion gene. He was initially managed with hydroxyurea, and given the aggressive nature of this disease, four months later, the patient underwent an allogeneic hematopoietic stem-cell transplantation (HSCT) from an HLA-haploidentical relative. Currently, HSCT may be the only therapeutic option for long-term survival at least until more efficacious tyrosine kinase inhibitors (TKIs) become available.

8p11 Myeloproliferative syndrome with t(8;22)(p11;q11): A case report

The 8p11 myeloproliferative syndrome (EMS), a rare myeloproliferative disease, generally progresses rapidly and is characterized by chromosomal translocations of the fibroblast growth factor receptor 1 (FGFR1) gene. The FGFR1 gene is located at chromosome 8p11 and may fuse with distinct partner genes. The breakpoint cluster region gene located at chromosome 22 is one of these partner genes. The patients' clinical phenotype is primarily dependant on the partner gene that translocates with FGFR1. Of all the available examinations, determination of the chromosome karyotype is most essential for the diagnosis of EMS. In addition, regarding treatment, allogeneic hematopoietic stem cell transplantation is currently the optimal method. The present study presented a case of 8p11 myeloproliferative syndrome with t(8;22)(p11;q11). This represents a total of 8 and 11 chromosomal translocations, which form a BCR/FGFR1 fusion gene in the patient to produce the abnormal karyotype: 46,XY,t(8;22)(p11;q11). The difference between the current case and other EMS incidences is that the patient progressed slowly and the clinical manifestation was similar to chronic myeloid leukemia (CML).

Chronic myelogenous leukemia-like hematological malignancy with t(8;22) in a 26-year-old pregnant woman: A case report

t(8;22)(p11;q11) is a rare but recurrent genetic alteration in various hematological disorders. Patients with t(8;22)(p11;q11) may be misdiagnosed with chronic myelogenous leukemia (CML), due to the similar clinical features. Thus, the current study presents a patient with t(8;22)(p11;q11) who was previously misdiagnosed with CML in the chronic phase. The current patient was a 26-year-old woman who was 4-weeks pregnant and in whom an increased white blood cell count (4.0×10¹⁰/l) was found upon physical examination. The patient had no history of hematological disease. Although cytogenetics showed a normal karyotype and no breakpoint cluster region/Abelson murine leukemia viral oncogene homolog 1 (BCR/ABL) fusion gene was detected by reverse transcription-polymerase chain reaction, a diagnosis of chronic myelogenous leukemia (CML) was initially made according to the clinical and morphological features. Another 6 weeks later, t(8;22)(p11;q11) rearrangement was present in 9 out of 10 analyzed metaphases. Fluorescence in situ hybridization and reverse transcription-polymerase chain reaction indicated a negative result for the BCR/ABL fusion, but gave a positive result for the BCR-fibroblast growth factor receptor 1 fusion. A hematological diagnosis of atypical CML was again formed.

Myeloid and lymphoid neoplasm with abnormalities of FGFR1 presenting with trilineage blasts and RUNX1 rearrangement: a case report and review of literature

OBJECTIVES

Myeloid and lymphoid neoplasms with abnormalities of fibroblast growth factor receptor 1 gene (FGFR1) are a rare and aggressive disease group that harbors translocations of FGFR1 with at least 14 recognized partner genes. We report a case of a patient with a novel t(17;21)(p13;q22) with RUNX1 rearrangement and trilineage blasts.

METHODS

A 29-year-old man with relapsed T-lymphoblastic lymphoma in the cervical nodes showed a myeloproliferative neoplasm in his bone marrow with three separate populations of immunophenotypically aberrant myeloid, T-lymphoid, and B-lymphoid blasts by flow cytometry. Cytogenetic and fluorescent in situ hybridization studies showed unique dual translocations of t(8;13)(p11.2;q12) and t(17;21)(p13;q22) with RUNX1 rearrangement.

RESULTS

The patient was initiated on a mitoxantrone, etoposide, and cytarabine chemotherapy regimen and died of complications of disease 1 month later.

CONCLUSIONS

To our knowledge, this is the first reported case of a myeloid and lymphoid neoplasm with abnormalities of FGFR1 with t(17;21)(p13;q22) and trilineage blasts.

A ZMYM2-FGFR1 8p11 myeloproliferative neoplasm with a novel nonsense RUNX1 mutation and tumor lysis upon imatinib treatment

The 8p11 myeloproliferative neoplasm (8p11 MPN) is a rare disorder that is molecularly characterized by fusions of diverse partners to the tyrosine kinase receptor gene FGFR1. It can rapidly transform to acute myeloid leukemia. Here we report on a case with a t(8;13)(p11.2;q12.1) ZMYM2-FGFR1 fusion, with massive tumor lysis upon tyrosine kinase inhibition with imatinib. Upon reevaluation, we detected trisomy 21 in addition to the translocation. Sequencing revealed a nonsense c.958C →T RUNX1 mutation both at diagnosis and disease progression, resulting in a p.Arg320X carboxyl-terminal truncated RUNX1 protein. This is the first report on an 8p11 MPN with a trisomy 21 RUNX1 mutation.

Acute leukemia showing t(8;22)(p11;q11), myelodysplasia, CD13/CD33/CD19 expression and immunoglobulin heavy chain gene rearrangement

t(8;22)(p11;q11) is a rare but recurrent chromosome translocation that has been reported in 11 cases of myeloproliferative neoplasm or B-acute lymphoblastic leukemia. This translocation results in an in-frame fusion of FGFR1 on 8p11 and BCR on 22q11, and causes constitutive activation of the tyrosine kinase of the BCR/FGFR1 chimera protein. Here, we report the twelfth case of hematological tumor bearing t(8;22)(p11;q11). The bone marrow showed hypoplastic and tri-lineage dysplasia with 24.4% abnormal cells. The abnormal cells were not defined as myeloid or lymphoid morphologically, lacking a myeloperoxidase reaction. Flow cytometric analysis of the bone marrow cells revealed that the abnormal cells expressed CD13, CD33, CD34, and CD19, and that a fraction of the abnormal cells was positive for CD10. Southern blot analysis of the bone marrow cells showed rearrangement of the immunoglobulin heavy chain gene, a genetic hallmark of B-cell differentiation. Previously reported cases with t(8;22)(p11;q11) suggested an association between myeloid and B-lymphoid tumors, whereas other chromosome translocations involving FGFR1 on 8p11 showed a link between myeloid and T-lymphoid tumors. Our observation supports that t(8;22)(p11;q11) might define a dual myeloid and B-lymphoid disorder.

A case of 8p11 myeloproliferative syndrome with BCR-FGFR1 gene fusion presenting with trilineage acute leukemia/lymphoma, successfully treated by cord blood transplantation

The 8p11 myeloproliferative syndrome is a rare neoplasm associated with chromosomal translocations involving the fibroblast growth factor receptor 1 (FGFR1) gene located at chromosome 8p11-12. FGFR1 encodes a transmembrane receptor tyrosine kinase. The resultant fusion proteins are constitutively active tyrosine kinases that drive the proliferation of hematopoietic cells, whose uncontrolled growth can present as a myeloproliferative neoplasm. We report here the case of a 50-year-old man harboring the t(8;22)(p12;q11) chromosomal translocation in cells from both bone marrow and lymph nodes. He presented with acute leukemia and lymphoma with trilineage features. A novel mRNA in-frame fusion between exon 4 of the breakpoint cluster region (BCR) gene at chromosome 22q11 and exon 9 of FGFR1 gene on chromosome 8p11-12 was identified by reverse transcription polymerase chain reaction analysis and was confirmed by DNA sequencing. Because the patient was refractory to chemotherapy, cord blood transplantation was performed in progressive disease. It resulted in a successful outcome in which cytogenetic complete remission has been maintained for 2 years till date.

Allogeneic Hematopoietic Stem Cell Transplantation for a BCR-FGFR1 Myeloproliferative Neoplasm Presenting as Acute Lymphoblastic Leukemia

Hematopoietic myeloproliferative neoplasms (MPNS) with rearrangements of the receptor tyrosine kinase FGFR1 gene, located on chromosome 8p11, are uncommon and associated with diverse presentations such as atypical chronic myeloid leukemia, acute myeloid leukemia, or an acute T- or B-lymphoblastic leukemia, reflecting the hematopoietic stem cell origin of the disease. A review of MPN patients with the t(8;22) translocation that results in a chimeric BCR-FGFR1 fusion gene reveals that this disease either presents or rapidly transforms into an acute leukemia that is generally unresponsive to currently available chemotherapeutic regimens including tyrosine kinase inhibitors (TKIS). The first case of a rare BCR-FGFR1 MPN presenting in a B-acute lymphoblastic phase who underwent allogeneic hematopoietic stem cell transplantation (HSCT) with a subsequent sustained complete molecular remission is described. Allogeneic HSCT is currently the only available therapy capable of achieving long-term remission in BCR-FGFR1 MPN patients.

Favorable outcome of allogeneic hematopoietic cell transplantation for 8p11 myeloproliferative syndrome associated with BCR-FGFR1 gene fusion

We report the case of a child who presented with nonspecific symptoms suggestive of a rheumatologic disorder, whose bone marrow had a complex translocation involving the FGFR1 locus. Hematopathologic findings were subtle and did not definitively indicate malignancy. Because he responded poorly to initial treatment with hydroxyurea, and in light of the progressive clinical course associated with the 8p11 myeloproliferative syndrome, he underwent an unrelated-donor hematopoietic stem cell transplant. This patient's atypical presentation highlights the importance of obtaining cytogenetic analysis at the time of bone marrow sampling and considering this uncommon entity in the differential diagnosis of hematologic disorders.

Acute progression of BCR-FGFR1 induced murine B-lympho/myeloproliferative disorder suggests involvement of lineages at the pro-B cell stage

Constitutive activation of FGFR1, through rearrangement with various dimerization domains, leads to atypical myeloproliferative disorders where, although T cell lymphoma are common, the BCR-FGFR1 chimeric kinase results in CML-like leukemia. As with the human disease, mouse bone marrow transduction/transplantation with BCR-FGFR1 leads to CML-like myeloproliferation as well as B-cell leukemia/lymphoma. The murine disease described in this report is virtually identical to the human disease in that both showed bi-lineage involvement of myeloid and B-cells, splenomegaly, leukocytosis and bone marrow hypercellularity. A CD19⁺ IgM⁻ CD43⁺ immunophenotype was seen both in primary tumors and two cell lines derived from these tumors. In all primary tumors, subpopulations of these CD19⁺ IgM⁻ CD43⁺ were also either B220⁺ or B220⁻, suggesting a block in differentiation at the pro-B cell stage. The B220⁻ phenotype was retained in one of the cell lines while the other was B220⁺. When the two cell lines were transplanted into syngeneic mice, all animals developed the same B-lymphoblastic leukemia within 2-weeks. Thus, the murine model described here closely mimics the human disease with bilineage myeloid and B-cell leukemia/lymphoma which provides a representative model to investigate therapeutic intervention and a better understanding of the etiology of the disease.

Modeling the human 8p11-myeloproliferative syndrome in immunodeficient mice

The 8p11 myeloproliferative syndrome (EMS), also referred to as stem cell leukemia/lymphoma, is a chronic myeloproliferative disorder that rapidly progresses into acute leukemia. Molecularly, EMS is characterized by fusion of various partner genes to the FGFR1 gene, resulting in constitutive activation of the tyrosine kinases in FGFR1. To date, no previous study has addressed the functional consequences of ectopic FGFR1 expression in the potentially most relevant cellular context, that of normal primary human hematopoietic cells. Herein, we report that expression of ZMYM2/FGFR1 (previously known as ZNF198/FGFR1) or BCR/FGFR1 in normal human CD34(+) cells from umbilical-cord blood leads to increased cellular proliferation and differentiation toward the erythroid lineage in vitro. In immunodeficient mice, expression of ZMYM2/FGFR1 or BCR/FGFR1 in human cells induces several features of human EMS, including expansion of several myeloid cell lineages and accumulation of blasts in bone marrow. Moreover, bone marrow fibrosis together with increased extramedullary hematopoiesis is observed. This study suggests that FGFR1 fusion oncogenes, by themselves, are capable of initiating an EMS-like disorder, and provides the first humanized model of a myeloproliferative disorder transforming into acute leukemia in mice. The established in vivo EMS model should provide a valuable tool for future studies of this disorder.

8p11 myeloproliferative syndrome: a review

The 8p11 myeloproliferative syndrome is an aggressive neoplasm associated with chromosomal translocations involving the fibroblast growth factor receptor 1 tyrosine kinase gene on chromosome 8p11-12. By our count, 65 cases are currently reported in the literature. This neoplasm affects patients of all ages, with a slight male predominance. Patients often present with peripheral blood eosinophilia without basophilia. Bone marrow examination commonly is hypercellular, with or without eosinophilia, which usually leads to the initial diagnosis of a myeloproliferative neoplasm. Many patients also present with or develop lymphadenopathy. Lymph node biopsy in these patients has commonly shown lymphoblastic leukemia/lymphoma, most often reported as being of T-cell lineage, but bilineal myeloid/T-cell lymphomas and less often a myeloid sarcoma are also reported. The natural history of this neoplasm is to evolve into acute leukemia, usually of myeloid or mixed lineage, and less frequently of T- or B-lymphoid lineage. The prognosis is poor despite aggressive chemotherapy, with a few patients achieving long clinical remission after stem cell transplantation. At the molecular level, all cases carry a chromosomal abnormality involving the fibroblast growth factor receptor 1 (FGFR1) gene at chromosome 8p11, where 10 translocations and 1 insertion have been identified. These abnormalities disrupt the FGFR1 and various partner genes, and result in the creation of novel fusion genes and chimeric proteins. The latter include the N-terminal portion of the partner genes and the C-terminal portion of FGFR1. The most common partner is ZNF198 on chromosome 13q12. In the current World Health Organization classification, the 8p11 myeloproliferative syndrome is designated as "myeloid and lymphoid neoplasms with FGFR1 abnormalities."