Canonical BAF complex regulates the oncogenic program in human T-cell acute lymphoblastic leukemia.

ABSTRACT: Acute leukemia cells require bone marrow microenvironments, known as niches, which provide leukemic cells with niche factors that are essential for leukemic cell survival and/or proliferation. However, it remains unclear how the dynamics of the leukemic cell-niche interaction are regulated. Using a genome-wide CRISPR screen, we discovered that canonical BRG1/BRM-associated factor (cBAF), a variant of the switch/sucrose nonfermenting chromatin remodeling complex, regulates the migratory response of human T-cell acute lymphoblastic leukemia (T-ALL) cells to a niche factor CXCL12. Mechanistically, cBAF maintains chromatin accessibility and allows RUNX1 to bind to CXCR4 enhancer regions. cBAF inhibition evicts RUNX1 from the genome, resulting in CXCR4 downregulation and impaired migration activity. In addition, cBAF maintains chromatin accessibility preferentially at RUNX1 binding sites, ensuring RUNX1 binding at these sites, and is required for expression of RUNX1-regulated genes, such as CDK6; therefore, cBAF inhibition negatively impacts cell proliferation and profoundly induces apoptosis. This anticancer effect was also confirmed using T-ALL xenograft models, suggesting cBAF as a promising therapeutic target. Thus, we provide novel evidence that cBAF regulates the RUNX1-driven leukemic program and governs migration activity toward CXCL12 and cell-autonomous growth in human T-ALL.

Unrelated hematopoietic stem cell transplantation for familial platelet disorder/acute myeloid leukemia with germline RUNX1 mutations.

Germline mutations in RUNX1 result in rare autosomal-dominant familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML). As genetic analysis is becoming increasingly prevalent, the diagnosis rate of FPD/AML is expected to increase. In this report, we present two pedigrees, one diagnosed molecularly and another highly suspected to be FPD/AML, whose members both received allogeneic hematopoietic stem cell transplantation (HSCT). Both pedigrees had a family history of thrombocytopenia, platelet dysfunction, and hematological malignancies. One family inherited a frameshift mutation (p.P240fs) of RUNX1, a known pathogenic variant. Another family inherited a point mutation (p.G168R) in the runt-homology domain, the clinical significance of which is uncertain at this point. As this mutation was completely absent from all population databases and had a relatively high REVEL score of 0.947, we thought that it would be dangerous to ignore its possible pathogenicity. Consequently, we avoided choosing HSCT donors from relatives of both families and performed HSCT from unrelated donors. In conclusion, our experience with two families of FPD/AML highlights the importance of searching for gene mutations associated with germline predisposition and indicates the necessity of developing a donor coordination system for FPD/AML patients, as well as a support system for families.

Granulocyte Colony-Stimulating Factor Administration at 1 Hour Before 18F-FDG PET Does Not Increase Bone Marrow FDG Accumulation.

ABSTRACT: A 74-year-old man with diffuse large B-cell lymphoma underwent 18F-FDG PET/CT to evaluate the response to chemotherapy. Although granulocyte colony-stimulating factor was incidentally administered 1 hour before FDG administration, bone marrow FDG accumulation did not increase compared with the previous 18F-FDG PET/CT examination without granulocyte colony-stimulating factor administration. The mean SUVmax of 12 thoracic and 5 lumbar vertebrae was 2.55 (range, 2.14-3.36) and 3.19 (range, 2.49-4.28) in the present and previous examinations, respectively.

[Autologous peripheral blood stem cell transplantation for treating primary central nervous system lymphoma: a single-center retrospective study].

Primary central nervous system lymphoma (PCNSL) is more difficult to treat than other lymphomas. Recently, it has been suggested that high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is effective for treating PCNSL. In the present study, we retrospectively analyzed 12 patients with PCNSL at our hospital. Five young patients with good performance status (PS) received upfront ASCT. The conditioning regimen prior to ASCT with busulfan ＋ cyclophosphamide ＋ etoposide showed good prognosis (complete remission rate of 100%). In addition, the PS improved in patients treated with high-dose chemotherapy followed by ASCT, while it worsened in those treated without ASCT. Further investigations are needed to clarify inclusion/exclusion criteria and optimize conditioning regimens for ASCT.

Multiple Myeloma Presenting with Autoimmune Autonomic Ganglionopathy.

Autoimmune autonomic ganglionopathy is an autonomic disorder that occurs as a symptom of paraneoplastic neurological syndrome. To date, there have been no reports on multiple myeloma with autoimmune autonomic ganglionopathy. A 37-year-old Japanese woman suffered from orthostatic hypotension was diagnosed with multiple myeloma (IgG kappa type), and a serological examination revealed the presence of anti-ganglionic nicotinic acetylcholine receptor (anti-gAChR) antibodies. She was treated for multiple myeloma, as a result, the autonomic disturbance improved and her anti-gAChR antibody titer decreased to undetectable levels, despite the fact that she only achieved a partial remission of multiple myeloma. Treatment for multiple myeloma may improve autoimmune autonomic ganglionopathy.

Dose-Modified Ifosfamide, Epirubicin, and Etoposide is a Safe and Effective Salvage Therapy with High Peripheral Blood Stem Cell Mobilization Capacity for Poorly Mobilized Hodgkin's Lymphoma and Non-Hodgkin's Lymphoma Patients.

A dose modified ifosfamide, epirubicin, and etoposide (IVE) regimen was prospectively assessed for its efficacy in mobilizing peripheral blood stem cells for autologous transplantation. Two patients with Hodgkin's lymphoma and two with non-Hodgkin's lymphoma who were undergoing stem cell therapy were studied. All patients had a history of multiple treatments with insufficient stem cell mobilization. The dose modified IVE regimen consisted of ifosfamide 3 g/m(2) intravenously (IV) administered on days 1-2 in combination with epirubicin 50 mg/m(2) IV on day 1 and etoposide 200 mg/m(2) (100 mg/m(2) in two patients with complete remission) IV on days 1-3. The ifosfamide dosage was reduced to two-thirds of the original protocol. A substantial high yield of CD34(+) cells was achieved when patients were treated with a dose-modified IVE regimen, compared with that during the previous regimen (two with the ifosfamide, carboplatin, and etoposide [ICE] regimen, one with high-dose cyclophosphamide and one with the original IVE regimen). Two patients who had refractory and residual disease received a 200 mg/m(2) dose of etoposide, which resulted in tumor reduction (one patient with complete remission and one with further reduction in tumor size). After the IVE regimen, all four patients had a sufficient yield of CD34(+) cells in total, which was available for stem cell transplantation. Hematological and non-hematological toxicities were comparable in all regimens. This single-center prospective study demonstrated that the dose-modified IVE regimen can be used as a safe treatment with high mobilizing efficacy in heavily pretreated lymphoma patients.