Miscreant myeloproliferative disorder stem cells

Extramedullary hematopoiesis: Elucidating the function of the hematopoietic stem cell niche (Review)

“…In contrast to how endothelial and perivascular cells and autonomic nerve systems maintain HSCs in the bone marrow (11,54) and how endosteal niches may maintain lymphoid progenitor cells (55), CXCL12-positive endothelial cells in the EMH-positive spleen may only contribute to the localization of HSCs to EMH-positive organs (5,56,57). As the results of a previous study indicated, CXCL12 is expressed in the sinus endothelial cells of the EMH-positive spleen, which may function in the entrapment of circulating hematopoietic precursor cells, whereas the cluster of macrophage/differentiated hematopoietic cells is separated from the CXCL12-positive endothelial cells (19).…”

Regulation of p27Kip1by mitogen-induced tyrosine phosphorylation

“…Mutation of valine 617 to phenylalanine (JAK2V617F) within its pseudokinase domain is one of the most common activating mutations of JAK2 and the most frequent mutation in BCR-Abl-negative myeloproliferative disorders. 82 JAK2V617F is expressed in up to 95% of polycythemia vera patients. [83][84][85][86] Expression of JAK2V617F leads to reduced p27 levels and to increased Y88 phosphorylation of p27.…”

Endogenous retrovirus induces leukemia in a xenograft mouse model for primary myelofibrosis

“…T he classic myeloproliferative neoplasms (MPN) are a heterogenous group of chronic disorders characterized by cellular proliferation of one or more myeloid lineages, which is thought to arise from a mutated hematopoietic stem cell (HSC) (1,2). Progression of the diseases from a neoplastic (precancerous) to an aggressive malignant (leukemia) stage is quite variable in rate and incidence, but forebodes a poor prognosis.…”