LABORATORY RESEARCH Hematopoietic Stem Cells Lacking Ott1 Display Aspects Associated with Aging and Are Unable to Maintain Quiescence during Proliferative Stress Scientists showed, specifically under replicative stress, one-twenty-two-1 (Ott1)-deleted hematopoietic stem cells had a significant reduction of the G0 cell cycle fraction associated with self-renewal and underwent early failure. [Blood] Abstract Human Extramedullary Bone Marrow in Mice: A Novel In Vivo Model of Genetically Controlled Hematopoietic Microenvironment Investigators described the development of extramedullary bone and bone marrow using human mesenchymal stromal cells and endothelial colony-forming cells implanted subcutaneously into immunodeficient mice. [Blood] Abstract Zebrafish Screen Identifies Novel Compound with Selective Toxicity against Leukemia To detect targeted anti-leukemia agents researchers designed a novel, high-content in vivo screen using genetically engineered, T cell-reporting zebrafish. [Blood] Abstract | Press Release Deletion of Tmprss6 Attenuates the Phenotype in a Mouse Model of β-Thalassemia Researchers showed that homozygous loss of Tmprss6 in Hbbth3/+ mice improved anemia and reduced ineffective erythropoiesis, splenomegaly and iron loading. [Blood] Abstract Using Combination Therapy to Override Stromal-Mediated Chemoresistance in Mutant FLT3-Positive AML: Synergism between FLT3 Inhibitors, Dasatinib/Multi-Targeted Inhibitors, and Janus Kinase Inhibitors Scientists used a cell-based model mimicking stromal protection as part of an unbiased high-throughput chemical screen to identify kinase inhibitors with the potential to override microenvironment-mediated drug resistance in mutant FLT3-positive acute myeloid leukemia (AML). [Leukemia] Abstract TET2 Is Essential for Survival and Hematopoietic Stem Cell Homeostasis To study the function of ten-eleven-translocation 2 (TET2) in vivo, researchers analyzed Ayu17-449 mice, in which a gene trap insertion in intron 2 of TET2 reduced TET2 mRNA levels to about 20% of that found in wild-type mice. [Leukemia] Abstract Human Olfactory Mucosa Multipotent Mesenchymal Stromal Cells Promote Survival, Proliferation and Differentiation of Human Hematopoietic Cells Researchers investigated whether human olfactory mucosa-mesenchymal stromal cells promote the survival, proliferation and differentiation of human hematopoietic stem cells. [Stem Cells Dev] Abstract Histone Deacetylase 3 (HDAC-3) Modulates the Expansion of Human Hematopoietic Stem Cells Scientists identified the valproic acid target HDAC3 as a negative regulator of umbilical cord blood hematopoietic stem cell expansion. [Stem Cells Dev] Abstract CLINICAL RESEARCH Effect of Gemtuzumab Ozogamicin on Survival of Adult Patients with De Novo Acute Myeloid Leukemia (ALFA-0701): A Randomized, Open-Label, Phase III Study Scientists investigated whether the addition of low fractionated-dose gemtuzumab ozogamicin to standard front-line chemotherapy would improve the outcome of patients with acute myeloid leukemia without causing excessive toxicity. [Lancet] Abstract | Press Release Alemtuzumab in Combination with Methylprednisolone Is a Highly Effective Induction Regimen for Patients with Chronic Lymphocytic Leukemia and Deletion of TP53: Final Results of the National Cancer Research Institute CLL206 Trial In an attempt to improve the treatment of TP53-defective chronic lymphocytic leukemia (CLL), a multicenter phase II study was developed to evaluate alemtuzumab and methylprednisolone in combination. [J Clin Oncol] Abstract |