Clonal evolution of 8p11 stem cell syndrome in a 14-year-old Chinese boy: a review of literature of t(8;13) associated myeloproliferative diseases

Hematological Neoplasms with Eosinophilia

Eosinophils in peripheral blood account for 0.3-5% of leukocytes, which is equivalent to 0.05-0.5 × 109/L. A count above 0.5 × 109/L is considered to indicate eosinophilia, while a count equal to or above 1.5 × 109/L is defined as hypereosinophilia. In bone marrow aspirate, eosinophilia is considered when eosinophils make up more than 6% of the total nuclear cells. In daily clinical practice, the most common causes of reactive eosinophilia are non-hematologic, whether they are non-neoplastic (allergic diseases, drugs, infections, or immunological diseases) or neoplastic (solid tumors). Eosinophilia that is associated with a hematological malignancy may be reactive or secondary to the production of eosinophilopoietic cytokines, and this is mainly seen in lymphoid neoplasms (Hodgkin lymphoma, mature T-cell neoplasms, lymphocytic variant of hypereosinophilic syndrome, and B-acute lymphoblastic leukemia/lymphoma). Eosinophilia that is associated with a hematological malignancy may also be neoplastic or primary, derived from the malignant clone, usually in myeloid neoplasms or with its origin in stem cells (myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions, acute myeloid leukemia with core binding factor translocations, mastocytosis, myeloproliferative neoplasms, myelodysplastic/myeloproliferative neoplasms, and myelodysplastic neoplasms). There are no concrete data in standardized cytological and cytometric procedures that could predict whether eosinophilia is reactive or clonal. The verification is usually indirect, based on the categorization of the accompanying hematologic malignancy. This review focuses on the broad differential diagnosis of hematological malignancies with eosinophilia.

Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase fusion genes: A workshop report with focus on novel entities and a literature review including paediatric cases

Myeloid/lymphoid neoplasms with eosinophilia (M/LN-eo) and tyrosine kinase (TK) gene fusions are a rare group of haematopoietic neoplasms with a broad range of clinical and morphological presentations. Paediatric cases have increasingly been recognised. Importantly, not all appear as a chronic myeloid neoplasm and eosinophilia is not always present. In addition, standard cytogenetic and molecular methods may not be sufficient to diagnose M/LN-eo due to cytogenetically cryptic aberrations. Therefore, additional evaluation with fluorescence in-situ hybridisation and other molecular genetic techniques (array-based comparative genomic hybridisation, RNA sequencing) are recommended for the identification of specific TK gene fusions. M/LN-eo with JAK2 and FLT3-rearrangements and ETV6::ABL1 fusion were recently added as a formal member to this category in the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In addition, other less common defined genetic alterations involving TK genes have been described. This study is an update on M/LN-eo with TK gene fusions with focus on novel entities, as illustrated by cases submitted to the Bone Marrow Workshop, organised by the European Bone Marrow Working Group (EBMWG) within the frame of the 21st European Association for Haematopathology congress (EAHP-SH) in Florence 2022. A literature review was performed including paediatric cases of M/LN-eo with TK gene fusions.

Pediatric 8p11 eosinophilic myeloproliferative syndrome (EMS): A case report and review of the literature

The 8p11 eosinophilic myeloproliferative syndrome (EMS) is an aggressive neoplasm driven by translocation of the fibroblast growth factor receptor 1 and often transforms to leukemias and lymphomas that are refractory to treatment. The first case was identified in 1983, and to date over 70 cases have been reported in the literature. Despite those reports, no consensus exists on management of this condition, and inconsistency in treatment regimens is even more pronounced in the pediatric literature. We report a case of a male infant with the 8p11 EMS, review the published pediatric experience with EMS, and discuss treatment strategies for this enigmatic hematological disorder.

[Clinical and gene involved of one case of 8p11 myeloproliferative syndrome with ins(13;8)(q12;p11p23)]

目的

提高对伴有染色体插入易位ins(13;8)(q12;p11p23）形成ZNF198-FGFR1融合基因的罕见疾病8p11骨髓增殖综合征(EMS)的认识，并对该融合基因进行全长克隆及结构分析。

方法

报道1例伴ins(13;8)(q12;p11p23）形成ZNF198-FGFR1融合基因的EMS患者的临床表现、实验室特征及诊治经过，并通过重叠PCR及TA克隆对该融合基因进行全长扩增及克隆测序。

结果

常规染色体核型分析发现1例ins(13;8)(q12;p11p23）患者，其临床特征主要为外周血白细胞计数明显升高、髓系高度增生、淋巴结肿大、快速向白血病转化趋势等；荧光原位杂交显示FGFR1基因重排，RT-PCR及直接测序证实ZNF198-FGFR1融合基因阳性，对该融合基因全长克隆及克隆测序证实其保留了各自的主要功能结构域。

结论

染色体插入易位ins(13;8)(q12;p11p23）形成ZNF198-FGFR1融合基因，该融合基因保留了主要功能结构域，伴有该基因阳性患者具有独特的实验室及临床特征。

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.

Functional roles of fibroblast growth factor receptors (FGFRs) signaling in human cancers

The fibroblast growth factor receptors (FGFRs) regulate important biological processes including cell proliferation and differentiation during development and tissue repair. Over the past decades, numerous pathological conditions and developmental syndromes have emerged as a consequence of deregulation in the FGFRs signaling network. This review aims to provide an overview of FGFR family, their complex signaling pathways in tumorigenesis, and the current development and application of therapeutics targeting the FGFRs signaling for treatment of refractory human cancers.

Ponatinib suppresses the development of myeloid and lymphoid malignancies associated with FGFR1 abnormalities

Myeloid and lymphoid malignancies associated with FGFR1 abnormalities are characterized by constitutive activated FGFR1 kinase and rapid transformation to acute myeloid leukemia and lymphoblastic lymphoma. Molecular targeted therapies have not been widely used for SCLL. Ponatinib (AP24534), that potently inhibits native and mutant BCR-ABL, also targets the fibroblast growth factor receptor (FGFR) family. Using murine BaF3 cells stably transformed with six different FGFR1 fusion genes, as well as human KG1 cells expressing activated chimeric FGFR1 and five newly established murine SCLL cell lines, we show that Ponatinib (< 50 nM) can effectively inhibit phosphoactivation of the fusion kinases and their downstream effectors, such as PLCγ, Stat5 and Src. Ponatinib also significantly extended survival of mice transplanted with different SCLL cell lines. Ponatinib administered at 30 mg/kg daily also significantly delayed, or even prevented, tumorigenesis of KG1 cells in xenotransplanted mice. Furthermore, we demonstrate that Ponatinib specifically inhibits cell growth and clonogenicity of normal human CD34+ progenitor cells transformed by chimeric FGFR1 fusion kinases. Overall, our data provide convincing evidence to suggest that pharmacologic inhibition of FGFR1 fusion kinases with Ponatinib is likely to be beneficial for patients with SCLL and perhaps for other human disorders associated with dysregulated FGFR1 activity.

Src activation plays an important key role in lymphomagenesis induced by FGFR1 fusion kinases

Chromosomal translocations and activation of the fibroblast growth factor (FGF) receptor 1 (FGFR1) are a feature of stem cell leukemia-lymphoma syndrome (SCLL), an aggressive malignancy characterized by rapid transformation to acute myeloid leukemia and lymphoblastic lymphoma. It has been suggested that FGFR1 proteins lose their ability to recruit Src kinase, an important mediator of FGFR1 signaling, as a result of the translocations that delete the extended FGFR substrate-2 (FRS2) interacting domain that Src binds. In this study, we report evidence that refutes this hypothesis and reinforces the notion that Src is a critical mediator of signaling from the FGFR1 chimeric fusion genes generated by translocation in SCLL. Src was constitutively active in BaF3 cells expressing exogenous FGFR1 chimeric kinases cultured in vitro as well as in T-cell or B-cell lymphomas they induced in vivo. Residual components of the FRS2-binding site retained in chimeric kinases that were generated by translocation were sufficient to interact with FRS2 and activate Src. The Src kinase inhibitor dasatinib killed transformed BaF3 cells and other established murine leukemia cell lines expressing chimeric FGFR1 kinases, significantly extending the survival of mice with SCLL syndrome. Our results indicated that Src kinase is pathogenically activated in lymphomagenesis induced by FGFR1 fusion genes, implying that Src kinase inhibitors may offer a useful option to treatment of FGFR1-associated myeloproliferative/lymphoma disorders.

Constitutive Notch pathway activation in murine ZMYM2-FGFR1-induced T-cell lymphomas associated with atypical myeloproliferative disease

The ZMYM2-FGFR1 (formerly known as ZNF198-FGFR1) fusion kinase induces stem cell leukemia-lymphoma syndrome (SCLL), a hematologic malignancy characterized by rapid transformation to acute myeloid leukemia and T-lymphoblastic lymphoma. In the present study, we demonstrate frequent, constitutive activation of Notch1 and its downstream target genes in T-cell lymphomas that arose in a murine model of ZMYM2-FGFR1 SCLL. Notch up-regulation was also demonstrated in human SCLL- and FGFR1OP2-FGFR1-expressing KG-1 cells. To study the role of Notch in T-cell lymphomagenesis, we developed a highly tumorigenic cell line from ZMYM2-FGFR1-expressing cells. Pharmacologic inhibition of Notch signaling in these cells using γ-secretase inhibitors significantly delayed leukemogenesis in vivo. shRNA targeting of Notch1, as well as c-promoter-binding factor 1 (CBF1) and mastermind-like 1 (MAML1), 2 essential cofactors involved in transcriptional activation of Notch target genes, also significantly delayed or inhibited tumorigenesis in vivo. Mutation analysis demonstrated that 5' promoter deletions and alternative promoter usage were responsible for constitutive activation of Notch1 in all T-cell lymphomas. These data demonstrate the importance of Notch signaling in the etiology of SCLL, and suggest that targeting this pathway could provide a novel strategy for molecular therapies to treat SCLL patients.

Biphenotypic hematologic malignancy: a case report of the 8p11 myeloproliferative syndrome in a child

The 8p11 myeloproliferative syndrome, also known as stem cell leukemia/lymphoma, is a rare, atypical, myeloproliferative disorder and lymphoid malignancy associated with chromosomal abnormalities involving the 8p11 chromosomal band. Translocations associated with this syndrome result in the fusion of the fibroblast growth factor receptor 1 (FGFR 1) gene with various partners, resulting in ligand-independent FGFR activity. To date, 8 partner genes have been identified in association with FGFR1 rearrangements. The most frequent FGFR1 translocation partner is the zinc finger gene ZNF198 located at 13q11. Disease phenotypes associated with this translocation include poor prognosis and transformation to acute leukemia and non-Hodgkin lymphoma. In common with a T-cell phenotype, obtaining and maintaining remission is difficult by conventional chemotherapy. This study describes an illustrative case of 8p11 myeloproliferative syndrome/stem cell leukemia/lymphoma outlining its chief features and historical developments.

Features of polycythemia vera in the 8p12 myeloproliferative syndrome

The 8p12 myeloproliferative syndrome is a distinct myeloid disorder associated with a translocation involving chromosome region 8p12 (HUGO nomenclature). It is characterized by leukocytosis, eosinophilia, and a concurrent or rapid transformation to a T-cell lymphoblastic lymphoma. We report a case of polycythemia vera as a clinical presentation of the 8p12 myeloproliferative syndrome and review the literature. Atypical features in patients with polycythemia vera should be investigated with cytogenetic evaluation.

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."

Molecular monitoring of 8p11 myeloproliferative syndrome in an infant

The 8p11 myeloproliferative syndrome is a rare hematologic malignancy derived from a pluripotent hematopoietic stem cell associated with rearrangements involving the fibroblast growth factor receptor 1 (FGFR1) gene located on chromosome 8p11. The most common translocation, t(8;13) (p11;q13), results in a ZNF198-FGFR1 fusion gene and constitutively active FGFR1 tyrosine kinase activity. Typical pathologic findings include myeloid hyperplasia, lymphadenopathy, precursor T-lymphoblastic lymphoma, and eosinophilia. The disease is usually associated with an aggressive course and progression to acute myeloid leukemia is frequent. We report here the first case of 8p11 myeloproliferative syndrome in an infant and demonstrate the value of molecular testing in the diagnosis and minimal disease monitoring of this rare disease.

Genetic fingerprinting of the development and progression of T-cell lymphoma in a murine model of atypical myeloproliferative disorder initiated by the ZNF198-fibroblast growth factor receptor-1 chimeric tyrosine kinase

A mouse model of human ZNF198-fibroblast growth factor receptor-1 (FGFR1) stem cell leukemia lymphoma has been developed to investigate mechanisms of oncogenesis and progression. Using array-based comparative genomic hybridization, we followed disease progression after serial transplantation of ZNF198-FGFR1-transformed stem cells that give rise to a distinct myeloproliferative disorder and T-lymphoblastic leukemia. A consistent, frequently homozygous, chr14:53880459-55011545 deletion, containing the T-cell receptor alpha and delta genes, was identified in the bone marrow, spleen, and lymph nodes in all cases. The absence of cell-surface T-cell receptor alpha in tumor cells precludes CD3 recruitment, resulting in loss of a functional T-cell receptor complex, supporting the idea that prevention of maturation of CD4(+)/CD8(+) double-positive immature T cells is important in ZNF198-FGFR1 disease development. Up-regulation of the B-cell line 2, interleukin 7 receptor alpha and interleuking 2 receptor alpha prosurvival genes in these undifferentiated tumor precursor cells suggests one mechanism that allows them to escape apoptosis in the thymus. Thus, we have defined an important event in the process of ZNF198-FGFR1-induced T-cell leukemia.