June Takeda

Integrated molecular analysis of adult T cell leukemia/lymphoma

Adult T cell leukemia/lymphoma (ATL) is a peripheral T cell neoplasm of largely unknown genetic basis, associated with human T cell leukemia virus type-1 (HTLV-1) infection. Here we describe an integrated molecular study in which we performed whole-genome, exome, transcriptome and targeted resequencing, as well as array-based copy number and methylation analyses, in a total of 426 ATL cases. The identified alterations overlap significantly with the HTLV-1 Tax interactome and are highly enriched for T cell receptor–NF-κB signaling, T cell trafficking and other T cell–related pathways as well as immunosurveillance. Other notable features include a predominance of activating mutations (in PLCG1, PRKCB, CARD11, VAV1, IRF4, FYN, CCR4 and CCR7) and gene fusions (CTLA4-CD28 and ICOS-CD28). We also discovered frequent intragenic deletions involving IKZF2, CARD11 and TP73 and mutations in GATA3, HNRNPA2B1, GPR183, CSNK2A1, CSNK2B and CSNK1A1. Our findings not only provide unique insights into key molecules in T cell signaling but will also guide the development of new diagnostics and therapeutics in this intractable tumor.

Efficiency of high-dose cytarabine added to CY/TBI in cord blood transplantation for myeloid malignancy

Cord blood transplantation (CBT) is an effective therapeutic option for adults with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) after the conventional cyclophosphamide and total body irradiation (CY/TBI) regimen, but posttransplant relapse is still of high importance. High-dose cytarabine (HDCA) can be added to CY/TBI for an intensified regimen; however, its additional effects have not yet been completely elucidated. Therefore, we conducted a cohort study to compare the prognosis of HDCA/CY/TBI (n = 617) and CY/TBI (n = 312) in CBT for AML/MDS, using a Japanese transplant registry database. The median age was 40 years, and 86.2% of the patients had AML; high-risk disease was observed in 56.2% of the patients. The median follow-up period after CBT was approximately 3.5 years. Overall survival was significantly superior in the HDCA/CY/TBI group (adjusted hazard ratio [HR], 0.56; 95% confidence interval [CI], 0.45-0.69; P < .01), and tumor-related mortality was lower (HR, 0.50; P < .01). The incidence of grade II to IV acute graft-vs-host disease (aGVHD) and chronic GVHD was significantly higher in the HDCA/CY/TBI group (HR, 1.33 and 2.30, respectively), but not grade III to IV aGVHD. Incidence of infectious episodes showed no significant difference. Nonrelapse mortality was not increased by the addition of HDCA. Higher-dose CA (12 rather than 8 g/m(2)) was more effective, particularly in patients at high-risk for disease. This study is the first to show the superiority of HDCA/CY/TBI to CY/TBI in CBT for AML/MDS. A large-scale prospective study is warranted to establish new conditioning regimens including HDCA administration.

Frequent somatic mutations in epigenetic regulators in newly diagnosed chronic myeloid leukemia

Although tyrosine kinase inhibitors (TKIs) have significantly improved the prognosis of chronic myeloid leukemia (CML), the ability of TKIs to eradicate CML remains uncertain and patients must continue TKI therapy for indefinite periods. In this study, we performed whole-exome sequencing to identify somatic mutations in 24 patients with newly diagnosed chronic phase CML who were registered in the JALSG CML212 study. We identified 191 somatic mutations other than the BCR-ABL1 fusion gene (median 8, range 1–17). Age, hemoglobin concentration and white blood cell counts were correlated with the number of mutations. Patients with mutations ⩾6 showed higher rate of achieving major molecular response than those<6 (P=0.0381). Mutations in epigenetic regulator, ASXL1, TET2, TET3, KDM1A and MSH6 were found in 25% of patients. TET2 or TET3, AKT1 and RUNX1 were mutated in one patient each. ASXL1 was mutated within exon 12 in three cases. Mutated genes were significantly enriched with cell signaling and cell division pathways. Furthermore, DNA copy number analysis showed that 2 of 24 patients had uniparental disomy of chromosome 1p or 3q, which disappeared major molecular response was achieved. These mutations may play significant roles in CML pathogenesis in addition to the strong driver mutation BCR-ABL1.

A novel genetic and morphologic phenotype of ARID2 -mediated myelodysplasia

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Successful treatment of high-risk acute promyelocytic leukemia in very elderly patients using all-trans retinoic acid plus reduced-dose idarubicin.

To the Editor,Theintroductionofall-transretinoicacid(ATRA)therapyhasmarkedly improved the outcome for younger patients withacute promyelocytic leukemia (APL) [1, 2]; however, theoptimal treatment regimen for elderly APL patients remainsunclearbecausefewpatientsover70yearsofageareincludedin clinical trials [3]. Here, we report the successful use ofATRA plus reduced-dose idarubicin to treat nonagenarianhigh-risk APL patients.Patient 1 (Fig. 1a), a 91-year-old woman with a previoushistory of hypertension and cerebral infarction, was admittedto our hospital with fever and bleeding. Her Eastern Cooper-ativeOncologyGroupPerformanceStatus(ECOG-PS)was4.Laboratoryresultswereasfollows:hemoglobin(Hb),103g/l;white blood cell (WBC) count, 36.2×109/l; platelet (Plt)count, 51×109/l; serum lactate dehydrogenase (LDH),1,437 IU/l; prothrombin time-international normalized ratio(PT-INR),1.41;activatedpartialthromboplastintime(APTT),34.5 s; fibrinogen, 157 mg/dl; and D-dimer, 315.7 μg/dl.Polymerase chain reaction analysis of peripheral blood cellsidentified the PML-RARα fusion gene. The patient receivedATRA (45 mg/m

Clonally related diffuse large B-cell lymphoma and interdigitating dendritic cell sarcoma sharing MYC translocation

Interdigitating dendritic cell sarcoma (IDCS) is a rare neoplasm considered to derive from a dendritic cell. Recent studies have shown that B- or T-lymphoblastic leukemia/lymphomas can develop clonally related histiocytic/dendritic cell (H/DC) neoplasms, such as histiocytic sarcoma, Langerhans cell