Cdk4 and Cdk6 Cooperate in Counteracting the INK4 Family of Inhibitors during Murine Leukemogenesis Cdk6 R31C impairs the potential of hematopoietic progenitors to repopulate upon adoptive transfer or after 5-fluorouracil-induced damage. The defects are overcome by eliminating sensitivity of cells to INK4 inhibitors by introducing the INK4-insensitive Cdk4 R24C allele, and INK4-resistant mice are more susceptible to hematopoietic and endocrine tumors. [Blood] Abstract | Press Release Progressive Maturation towards Hematopoietic Stem Cells in the Mouse Embryo Aorta Scientists show that intra-aortic hematopoietic clusters (IAHCs) contain pre-hematopoietic stem cells (HSCs) that can mature into HSCs in vivo. Such IAHC pre-HSCs could contribute to the HSC pool increase observed at mid-gestation. [Blood] Abstract Overexpression of ERG in Cord Blood Progenitors Promotes Expansion and Recapitulates Molecular Signatures of High ERG Leukemias Human CD34+ cells were transduced with retroviral vectors to elevate ERG gene expression to levels detected in high ERG acute myeloid leukemia. RNA sequencing was performed on purified populations of transduced cells to define the effects of high ERG on gene expression in human CD34+ cells. [Leukemia] Abstract Development of the Fetal Bone Marrow Niche and Regulation of HSC Quiescence and Homing Ability by Emerging Osteolineage Cells Little is known about bone marrow niche formation or the role of its cellular components in hematopoietic stem cell (HSC) development; therefore, researchers established the timing of murine fetal long bone vascularization and ossification relative to the onset of HSC activity. [Cell Rep] Full Article | Graphical Abstract Viability and Stress Protection of Chronic Lymphoid Leukemia Cells Involves Overactivation of Mitochondrial PhosphoSTAT3Ser727 Scientists report on a novel STAT3-mediated pathway that characterizes chronic lymphoid leukemia (CLL) B cells-extended viability and oxidative stress control. They observed that leukemic but not normal B cells from CLL patients exhibit constitutive activation of an atypical form of the STAT3 signaling factor, phosphorylated on serine 727 (Ser727) in the absence of detectable canonical tyrosine 705-dependent activation in vivo. [Cell Death Dis] Full Article A Designed Peptide Targeting CXCR4 Displays Anti-Acute Myelocytic Leukemia Activity In Vitro and In Vivo Researchers demonstrate that a novel designed peptide targeting CXCR4 inhibits stroma derived factor 1α- and stroma-induced activation in multiple acute myelocytic leukemia (AML) cell lines and displays anti-AML activity. [Sci Rep] Full Article CLINICAL RESEARCH Immunosuppressive Therapy of LGL Leukemia: Prospective Multicenter Phase II Study by the Eastern Cooperative Oncology Group (E5998) This prospective trial in large granular lymphocyte (LGL) leukemia was a multicenter, Phase II clinical trial evaluating methotrexate at 10 mg/m2 orally weekly as initial therapy. [Leukemia] Abstract Allogeneic Hematopoietic Stem Cell Transplantation for Infant Acute Lymphoblastic Leukemia with KMT2A (MLL) Rearrangements: A Retrospective Study from the Pediatric Acute Lymphoblastic Leukemia Working Group of the Japan Society for Hematopoietic Cell Transplantation Scientists retrospectively analyzed outcomes of hematopoietic stem cell transplantation (HSCT) in infants with acute lymphoblastic leukemia (ALL) based on nationwide registry data of the Japan Society for Hematopoietic Cell Transplantation. A total of 132 allogeneic HSCT for infant ALL with KMT2A (MLL) gene rearrangements, which were performed in first complete remission, were analyzed. [Br J Haematol] Abstract Monocytic and Promyelocytic Myeloid-Derived Suppressor Cells may Contribute to G-CSF-Induced Immune Tolerance in Haplo-Identical Allogeneic Hematopoietic Stem Cell Transplantation Researchers investigated the effects of granulocyte colony-stimulating factor (G-CSF) on monocytic, promyelocytic and granulocytic myeloid-derived suppressor cells (MDSCs) both in bone marrow and peripheral blood of 20 healthy donors and the association of MDSCs subgroups with acute and chronic graft-versus-host disease in 62 patients who underwent haplo-identical allogeneic hematopoietic stem cell transplantation. [Am J Hematol] Abstract |