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

Mechanisms of Secondary Leukemia Development Caused by Treatment with DNA Topoisomerase Inhibitors

Leukemia is a blood cancer originating in the blood and bone marrow. Therapy-related leukemia is associated with prior chemotherapy. Although cancer therapy with DNA topoisomerase II inhibitors is one of the most effective cancer treatments, its side effects include development of secondary leukemia characterized by the chromosomal rearrangements affecting AML1 or MLL genes. Recurrent chromosomal translocations in the therapy-related leukemia differ from chromosomal rearrangements associated with other neoplasias. Here, we reviewed the factors that drive chromosomal translocations induced by cancer treatment with DNA topoisomerase II inhibitors, such as mobility of ends of double-strand DNA breaks formed before the translocation and gain of function of fusion proteins generated as a result of translocation.

Recurrent Translocations in Topoisomerase Inhibitor-Related Leukemia Are Determined by the Features of DNA Breaks Rather Than by the Proximity of the Translocating Genes

Topoisomerase inhibitors are widely used in cancer chemotherapy. However, one of the potential long-term adverse effects of such therapy is acute leukemia. A key feature of such therapy-induced acute myeloid leukemia (t-AML) is recurrent chromosomal translocations involving AML1 (RUNX1) or MLL (KMT2A) genes. The formation of chromosomal translocation depends on the spatial proximity of translocation partners and the mobility of the DNA ends. It is unclear which of these two factors might be decisive for recurrent t-AML translocations. Here, we used fluorescence in situ hybridization (FISH) and chromosome conformation capture followed by sequencing (4C-seq) to investigate double-strand DNA break formation and the mobility of broken ends upon etoposide treatment, as well as contacts between translocation partner genes. We detected the separation of the parts of the broken AML1 gene, as well as the increased mobility of these separated parts. 4C-seq analysis showed no evident contacts of AML1 and MLL with loci, implicated in recurrent t-AML translocations, either before or after etoposide treatment. We suggest that separation of the break ends and their increased non-targeted mobility—but not spatial predisposition of the rearrangement partners—plays a major role in the formation of these translocations.

Acute Promyelocytic Leukemia Masquerading as Sero-negative Polyarthritis: Case Report

Musculoskeletal manifestations as the sole presentation in acute leukemia is rare in adults. Acute promyelocytic leukemia (APML) is a subtype of acute myeloid leukemia (AML) with reported incidence of 10 to 15% of total AML cases. APML presenting as polyarticular arthritis has never been reported in the literature. We present an interesting case of 20-year-old male patient who manifested with polyarticular arthritis mainly of small joints as the initial presentation, followed by pancytopenia and eventually was diagnosed as a case of APML on bone marrow morphology and molecular analysis for PML-RARα transcript. He was successfully treated with all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO). Arthritis also resolved with complete remission of APML. Arthritis in a case with pancytopenia should promptly be evaluated prior to treatment with steroids and anti-metabolites. Arthritis can be a presenting manifestation of APML and responds to prompt management of leukemia as in other cases of leukemic arthritis.

[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。

Cancer chemotherapeutics in rheumatoid arthritis: A convoluted connection

Chemotherapy is one of the most popular therapeutic strategies to treat cancer. However, cancer chemotherapeutics have often been associated with impairment of the immune system, which might consequently lead to an augmented risk of autoimmune disorders, such as rheumatoid arthritis. Though the accurate mechanistic facets of rheumatoid arthritis induction have not been interpreted yet, a conglomeration of genetic and environmental factors might promote its etiology. What makes the scenario more challenging is that patients with rheumatoid arthritis are at a significantly elevated risk of developing various types of cancer. It is intriguing to note that diverse cancer chemotherapy drugs are also commonly used to treat symptoms of rheumatoid arthritis. However, a colossal multitude of such cancer therapeutics has demonstrated highly varied results in rheumatoid arthritis patients, including both beneficial and adverse effects. Herein, we attempt to present a holistic account of the variegated modalities of this complex tripartite cross-talk between cancer, rheumatoid arthritis and chemotherapy drugs in order to decode the sinuous correlation between these two appalling pathological conditions.

H2AFY is a novel fusion partner of MECOM in acute myeloid leukemia

The MECOM gene encoding a zinc finger protein that functions as a transcription factor, was located on chromosome 3q26, and rearrangements of MECOM often cause its overexpression in acute myeloid leukemia (AML). We identified H2AFY as a novel fusion gene partner of MECOM in an elderly male AML patient with cryptic 3q26 rearrangement using the whole transcriptome sequencing, who carried out abnormal karyotype of 46,XY,t(3;5)(q27;q31),add(14)(p11). We validated the existence of the unreported H2AFY-MECOM fusion gene by RT-PCR and Sanger DNA sequencing, and detected mutations of NRAS and BCOR in this patient. In addition, we found abnormally elevated expression of MECOM in this patient by quantitative-polymerase chain reaction (RQ-PCR). Further research is needed to investigate functional characterizations of this novel fusion in the development of AML.