Blood cells play vital roles for the maintenance of organism integrity. Erythrocytes are responsible
for the oxygen supply, while platelets (originating from megakaryocytes) prevent blood loss. In
addition, the white blood cells ensure an appropriate immune defense against external (viruses,
microorganisms) and internal threats (e.g. tumors). All cellular blood components originate from
hematopoietic stem cells (HSCs) that reside in the bone marrow (BM). During hematopoietic
differentiation, HSCs progressively loss their capacity of self-renewal and the potential to give rise to
mature and functional blood cell types. This stepwise HSC specialization has to be tightly controlled
by molecular regulators because alterations in the process can result in uncontrolled cell growth
and/or differentiation block, thereby resulting in malignant transformation. The group of cancers
that originate from blood cells are defined as “leukemias”. Our research is dedicated to establish the
oncogenic role of a protein that is often deregulated in human blood malignancies using human
precursor cells. Such studies only have the highest clinical relevance when modified human
precursor cells are transplanted in mice because other systems can’t reproduce normal and
malignant human hematopoiesis precisely. These novel mouse models will be useful for leukemia
studies that will help us to understand pathogenesis of blood malignancies and that can be used for
pre-clinical tests of anti-leukemic drugs.