Acute promyelocytic leukemia relapsing as secondary acute myelogenous leukemia with translocation t(3;21)(q26;q22) and RUNX1–MDS1–EVI1 fusion transcript

A rare presentation of BCR-ABL1 and RUNX1-MECOM rearrangement in a pediatric patient with acute myeloid leukemia

Key Clinical Message

In a patient with de novo AML, co-existing BCR::ABL1 p190 isoform and RUNX1::MECOM rearrangement is accompanied by a very poor prognosis including limited response to treatment and no molecular remission. It is essential to develop a consensus on the therapeutic modalities different from the current regimen.

Abstract

Acquisition of BCR::ABL1 fusion as a primary or secondary event and RUNX1::MECOM fusion independently is reported in de novo and therapy-related MDS/AML, albeit with low frequency (<0.5%). Coexistence of BCR::ABL1 and MECOM translocation is known to cause leukemogenesis in animal models and progression towards blast crisis CML but not AML. Here we report a unique case of pediatric AML with concomitant BCR::ABL1 and RUNX1::MECOM fusion.Routine diagnostic work-up included WBC manual differential, immunophenotype, morphology, qPCR, FISH, and NGS-based CNV analyses. The patient presented with history of fever, dizziness, fatigue, gingival bleeding, and epistaxis associated with ecchymosis in right hand and heavy, prolonged menstrual period. At presentation, her hemoglobin was 5.3 g/dL, WBC 52.1(10*9/L), PLT 10(10*9/L), ESR 5 mm/h and LDH 2658 U/L. Bone marrow was hypercellular with 71% blasts, and flow cytometry showed myeloid markers including CD11c, CD33, CD34, and CD45 among others indicating AML with monocytic differentiation. FISH analyses showed variant t(9;22) (q34.1;q11.1), one additional copy each of chromosome 8 and Runx1 gene, while NGS-based CNV analyses revealed a terminal and proximal pathogenic gain within 9q34.12q34.3 and 22q11.1q11.23, respectively, and gain of entire chromosome 8 and 12 in mosaic state. qPCR confirmed the presence of p190 and also revealed RUNX1::MECOM fusion. Patient received ADE (cytarabine, daunorubicin, and etoposide) induction regimen but required multiple ICU admissions due to sepsis, cardiac shock, acute myocarditis, and thyroiditis. Coexisting BCR::ABL1 and RUNX1::MECOM fusion is suggestive of poor prognosis, and a need for consensus on the treatment modalities other than the current regimen is warranted.

BCR-ABL1-positive acute lymphoblastic leukemia following successful treatment of acute promyelocytic leukemia: case report

Acute promyelocytic leukemia (APL) is currently considered a disease with a higher cure rate. And cases of secondary malignant tumors following successful APL treatment are rare. Here we described a rare case of a 29-year-old man who was treated for APL in 2019 and developed BCR-ABL1-positive acute lymphoblastic leukemia 2 years later. The patient responded well to tyrosine kinase inhibitors and chemotherapy, and achieved a molecular remission. Although APL usually has a good prognosis, the prognosis of its secondary malignancies is uncertain. There are no effective measures to prevent the occurrence of secondary tumors. Continuing to increase the monitoring frequency of laboratory tests, especially the molecular biomarkers, is essential for the diagnosis and treatment of secondary malignancies after the patients achieving complete remission.

[Therapy-related myeloid neoplasms after successful treatment for acute promyelocytic leukemia: a report of four cases and literature review]

Objective: To investigate the clinical characteristics, diagnosis, treatment and prognosis of therapy-related myeloid neoplasms (t-MNs) after successful treatment for acute promyelocytic leukemia (APL) . Methods: Clinical data of 4 patients, diagnosed as t-MNs secondary to APL at Hematology Hospital of Chinese Academy of Medical Sciences from October 2012 to January 2019, were collected retrospectively. T-MNs related literature was reviewed. Results: The 4 cases were all females, with the median age 42 (range 40-53) years old at the diagnosis of APL. Regarding the induction and consolidation regimens, 3 patients received all-trans retinoid acid (ATRA) and arsenic trioxide (ATO) combined with anthracycline/anthraquinone and/or cytosine. One patient only received ATRA and other auxiliary drugs. Alkylating agents were not administrated. The 4 patients developed t-MNs 40 to 43 months after complete remission (CR) of APL, including 1 case of therapy-related myelodysplastic syndrome (t-MDS) and 3 cases of acute myeloid leukemia (t-AML) . The PML-RARα fusion genes were all negative when t-MNs developed. The three patients with t-AML were treated with 3 to 4 re-induction regimens, one of whom underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) after complete remission (CR) . One patient with t-MDS received hypomethylating agents. After a median follow-up of 54.5 (48-62) months, 2 patients with t-AML died, the median overall survival after t-MN was 12 (5-18) months. From 1989 to 2018, a total of 63 t-MN cases were reported in the literature. Therefore, 67 cases were analyzed when four patients in our center were added, including 27 males and 40 females with median age 52.5 (15-76) years. The median latency was 39 (12-126) months and the median overall survival after diagnosis of t-MN was 10 (1-39) months. Conclusions: Although rare, t-MNs may occur after successful control of APL. There are no existing guidelines for prevention and treatment of t-MNs, which have very poor prognosis. If cytopenia or other abnormalities of peripheral blood cells develop after 3 years of APL, t-MNs should be considered as a differential diagnosis.

[Clinical analysis of myeloid neoplasms with t (3;21) (q26;q22)]

目的

探讨伴有t（3;21）（q26;q22）髓系肿瘤的临床特征。

方法

回顾性分析2011年1月至2018年3月北京大学人民医院收治的19例伴有t（3;21）（q26;q22）血液恶性肿瘤患者的临床资料，并汇总文献报道的有详细生存资料的48例患者，采用Kaplan-Meier法进行生存分析。

结果

19例患者中男15例，女4例，中位年龄36（22~68）岁，包括原发急性髓系白血病（AML）4例，骨髓增生异常综合征（MDS）4例，MDS转化的AML3例，慢性髓性白血病（CML）急变8例。19例患者染色体核型均可见t（3;21）（q26;q22），其中13例伴有附加异常。19例中9例进行AML1-MDS1融合基因检测均阳性。9例患者有随访资料，6例接受化疗的患者中4例无效，2例获得完全缓解。随访期内除1例MDS患者因随访期短（6个月）仍存活，其余8例均死亡，中位生存时间为6（4.5~22）个月。汇总文献生存分析结果显示伴有t（3;21）（q26;q22）的髓系肿瘤患者整体预后差，中位生存时间为7个月，尤以AML/治疗相关的AML预后最差，移植和非移植组中位生存时间分别为20.9和4.7个月，差异有统计学意义（P<0.001）。

结论

t（3;21）（q26;q22）是罕见的重现性染色体异常，主要见于髓系血液肿瘤，临床预后差，建议尽早进行造血干细胞移植。

Acute myeloid leukemia with t(3;21)(q26.2;q22) developing following low-dose methotrexate therapy for rheumatoid arthritis and expressing two AML1/MDS1/EVI1 fusion proteins: A case report

The t(3;21)(q26.2;q22) translocation is a rare chromosomal abnormality exhibited almost exclusively in therapy-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/AML) or in the blastic crisis phase of chronic myelogenous leukemia, which results in the fusion of the runt related transcription factor 1 (RUNX1, also called AML1) gene at 21q22 to the myelodysplasia syndrome 1 (MDS1)-ecotropic virus integration site 1 (EVI1) complex locus (MECOM) at 3q26.2, generating various fusion transcripts, including AML1/MDS1/EVI1 (AME). The present study examined the case of an 84-year-old Japanese woman who developed t-MDS/AML with t(3;21)(q26.2;q22) subsequent to receiving low-dose methotrexate (MTX) treatment for rheumatoid arthritis. Following treatment with MTX for 6 years, the patient developed anemia and neutropenia, and MTX was discontinued. A total of 3 years later, the patient was diagnosed with MDS with t(3;21)(q26.2;q22) and del (5q), which progressed rapidly to AML within 3 months. The patients was subsequently treated with azacitidine and cytarabine chemotherapy, but succumbed to the disease 6 months after diagnosis. Sequencing analysis of the nested reverse transcription-PCR products from the leukemic cells revealed the expression of two types of alternatively-spliced AME transcripts with or without RUNX1 exon 6 sequences. Western blot analysis of the leukemic cells of the patient additionally revealed that the corresponding AME fusion protein products were expressed at high levels, and that these cells also prominently expressed CCAAT/enhancer-binding protein α, the repression of which has been reported to be involved in leukemogenesis mediated by AME. To the best of our knowledge, the case discussed in the present study represents the first report of MDS/AML with t(3;21)(q26.2;q22) developing following low-dose MTX therapy for rheumatoid arthritis. Nonetheless, the clinical and molecular features of the patient in the present study were representative of those patients who typically develop this disease following exposure to chemotherapy or radiotherapy for primary malignancy, which implicates MTX in the pathogenesis of t-MDS/AML. Moreover, we confirmed the expression of two AME fusion proteins for the first time in primary leukemic cells and analyzed several cellular factors implicated in AME-mediated leukemogenesis to gain some insight into its molecular mechanisms.

Recurrent Cytogenetic Abnormalities in Acute Myeloid Leukemia

The spectrum of chromosomal abnormality associated with leukemogenesis of acute myeloid leukemia (AML) is broad and heterogeneous when compared to chronic myeloid leukemia and other myeloid neoplasms. Recurrent chromosomal translocations such as t(8;21), t(15;17), and inv(16) are frequently detected, but hundreds of other uncommon chromosomal aberrations from AML also exist. This chapter discusses 22 chromosomal abnormalities that are common structural, numerical aberrations, and other important but infrequent (less than 1 %) translocations emphasized in the WHO classification. Brief morphologic, cytogenetic, and clinical characteristics are summarized, so as to provide a concise reference to cancer cytogenetic laboratories. Morphology based on FAB classification is used together with the current WHO classification due to frequent mentioning in a vast number of reference literatures. Characteristic chromosomal aberrations of other myeloid neoplasms such as myelodysplastic syndrome and myeloproliferative neoplasm will be discussed in separate chapters-except for certain abnormalities such as t(9;22) in de novo AML. Gene mutations detected in normal karyotype AML by cutting edge next generation sequencing technology are also briefly mentioned.

From molecular interaction to acute promyelocytic leukemia: Calculating leukemogenesis and remission from endogenous molecular-cellular network

Acute promyelocytic leukemia (APL) remains the best example of a malignancy that can be cured clinically by differentiation therapy. We demonstrate that APL may emerge from a dynamical endogenous molecular-cellular network obtained from normal, non-cancerous molecular interactions such as signal transduction and translational regulation under physiological conditions. This unifying framework, which reproduces APL, normal progenitor, and differentiated granulocytic phenotypes as different robust states from the network dynamics, has the advantage to study transition between these states, i.e. critical drivers for leukemogenesis and targets for differentiation. The simulation results quantitatively reproduce microarray profiles of NB4 and HL60 cell lines in response to treatment and normal neutrophil differentiation, and lead to new findings such as biomarkers for APL and additional molecular targets for arsenic trioxide therapy. The modeling shows APL and normal states mutually suppress each other, both in "wiring" and in dynamical cooperation. Leukemogenesis and recovery under treatment may be a consequence of spontaneous or induced transitions between robust states, through "passes" or "dragging" by drug effects. Our approach rationalizes leukemic complexity and constructs a platform towards extending differentiation therapy by performing "dry" molecular biology experiments.

An unusual case of splenomegaly and increased lactate dehydrogenase heralding acute myeloid leukemia with eosinophilia and RUNX1-MECOM fusion transcripts

We report the first case of acute myeloid leukemia (AML) with RUNX1-MECOM fusion transcripts, showing marked eosinophilia. A 63-year old man admitted in August 2013, had previously been observed in April 2013, because of persisting homogeneous splenomegaly and increased LDH, which were initially attributed to both minor β-thalassemia and previous acute myocardial infarction. However, based upon the retrospective analysis of clinical features combined with the documentation of both JAK2 V617F and c-KIT D816V mutations at AML diagnosis, an aggressive leukemic transformation with eosinophilia of a previously unrecognized myeloproliferative neoplasm, rather than the occurrence of de novo AML, may be hypothesized.

The role of topoisomerase II beta on breakage and proximity of RUNX1 to partner alleles RUNX1T1 and EVI1

Rearrangements involving the RUNX1 gene account for approximately 15% of balanced translocations in therapy-related acute myeloid leukemia (t-AML) patients and are one of the most common genetic abnormalities observed in t-AML. Drugs targeting the topoisomerase II (TOP2) enzyme are implicated in t-AML; however, the mechanism is not well understood and to date a single RUNX1-RUNX1T1 t-AML breakpoint junction sequence has been published. Here we report an additional five breakpoint junction sequences from t-AML patients with the RUNX1- RUNX1T1 translocation. Using a leukemia cell line model, we show that TOP2 beta (TOP2B) is required for induction of RUNX1 chromosomal breaks by the TOP2 poison etoposide and that, while TOP2 alpha (TOP2A) and TOP2B proteins are both present on RUNX1 and RUNX1T1 chromatin, only the TOP2B enrichment reached significance following etoposide exposure at a region on RUNX1 where translocations occur. Furthermore, we demonstrate that TOP2B influences the separation between RUNX1 and two translocation partners (RUNX1T1 and EVI) in the nucleus of lymphoid cells. Specifically, we identified a TOP2B-dependent increase in the number of nuclei displaying juxtaposed RUNX1 and RUNX1T1 loci following etoposide treatment.

Detection of RUNX1-MECOM fusion gene and t(3;21) in a very elderly patient having acute myeloid leukemia with myelodysplasia-related changes

An 87-yr-old woman was diagnosed with AML with myelodysplasia-related changes (AML-MRC). The initial complete blood count showed Hb level of 5.9 g/dL, platelet counts of 27×10⁹/L, and white blood cell counts of 85.33×10⁹/L with 55% blasts. Peripheral blood samples were used in all the tests, as bone marrow examination could not be performed because of the patient's extremely advanced age and poor general health condition. Flow cytometric analysis, chromosome analysis, FISH, and reverse transcriptase-PCR (RT-PCR) results indicated AML-MRC resulting from t(3;21) with the RUNX1-MECOM fusion gene. To our knowledge, this is the second most elderly de novo AML patient associated with t(3;21) to be reported.

Clinical and genetic features of therapy-related myeloid neoplasms after chemotherapy for acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a highly curable disease with excellent complete remission and long-term survival rates. However, the development of therapy-related myeloid neoplasms (t-MN) is being reported with increasing frequency in patients successfully treated for APL. We attempted to clarify the different clinical features and hematologic findings between t-MN and relapse cases, and to identify gene alterations involved in t-MN. We compared 10 relapse and 11 t-MN cases that developed in 108 patients during their first complete remission from APL. At APL diagnosis, t-MN patients had lower white blood cell counts than did relapse patients (P = .048). Overall survival starting from chemotherapy was significantly worse in t-MN patients than in relapse patients (P = .022). The t-MN cases were characterized as CD34(+)/HLA-DR(+) and PML-RARA(-), and 4 RUNX1/AML1 mutations were detected. T-MN is easily distinguished from APL relapse by evaluating these hematologic features, and it may originate from primitive myeloid cells by chemotherapy-induced RUNX1 mutations.

Repetitive busulfan administration after hematopoietic stem cell gene therapy associated with a dominant HDAC7 clone in a nonhuman primate

The risk of genotoxicity of retroviral vector-delivered gene therapy targeting hematopoietic stem cells (HSCs) has been highlighted by the development of clonal dominance and malignancies in human and animal gene therapy trials. Large-animal models have proven invaluable to test the safety of retroviral vectors, but the detection of clonal dominance may require years of follow-up. We hypothesized that hematopoietic stress may accelerate the proliferation and therefore the detection of abnormal clones in these models. We administered four monthly busulfan (Bu) infusions to induce hematopoietic stress in a healthy rhesus macaque previously transplanted with CD34+ cells transduced with retroviral vectors carrying a simple marker gene. Busulfan administration resulted in significant cytopenias with each cycle, and prolonged pancytopenia after the final cycle with eventual recovery. Before busulfan treatment there was highly polyclonal marking in all lineages. After Bu administration clonal diversity was markedly decreased in all lineages. Unexpectedly, we found no evidence of selection of the MDS1/EVI1 clones present before Bu administration, but a clone with a vector integration in intron 1 of the histone deacetylase-7 (HDAC7) gene became dominant in granulocytes over time after Bu administration. The overall marking level in the animal was increased significantly after Bu treatment and coincident with expansion of the HDAC7 clone, suggesting an in vivo advantage for this clone under stress. HDAC7 expression was upregulated in marrow progenitors containing the vector. Almost 5 years after Bu administration, the animal developed progressive cytopenias, and at autopsy the marrow showed complete lack of neutrophil or platelet maturation, with a new population of approximately 20% undifferentiated blasts. These data suggest that chemotherapeutic stress may accelerate vector-related clonal dominance, even in the absence of drug resistance genes expressed by the vector. This model may both accelerate the detection of abnormal clones to facilitate analysis of genotoxicity for human gene therapy, and help assess the safety of administering myelotoxic chemotherapeutic agents in patients previously engrafted with vector-containing cells.