Background: During embryonal development primitive hematopoiesis can be observed first in the yolk sac, in which both hematopoietic and endothelial cells are derived from a common precursor, the hemangioblast. Whether cells with this dual differentiation potential persist during postnatal life is unknown.
Methods: A cell line was derived from a patient with secondary acute leukemia. Because of its ability to grow in soft agar and in SCID mice, this cell line was analyzed for expression of differentiation antigens by fluorescence-activated cell sorter analysis, immunocytochemistry, fluorescent in situ hybridization (FISH) analysis with simultaneous cell surface staining, and polymerase chain reaction (PCR).
Results: A new cell line was established from a patient with essential thrombocytosis that transformed into acute leukemia. The patient's initial clinical presentation included skin and lymph node infiltrations that were taken for an angiosarcoma due to positivity for CD34, CD31, and von Willebrand factor on immunohistology. In addition to hematopoietic markers, leukemic cells expressed endothelial antigens such as CD62E, CD105, and bound Ulex europäeus lectin-1. Immunocytochemistry revealed positive staining for vascular endothelial growth factor receptor type 2 (KDR), Tie-2/Tek, the angiopoietin receptor, and vascular endothelial cadherin. These results were confirmed by PCR analysis. Simultaneous staining for CD62E and FISH analysis showed that cells with endothelial characteristics belonged to the leukemia. FISH analysis of histologic sections of the lymph node infiltration confirmed this manifestation as part of the leukemic process. The derived cell line, UKE-1, forms colonies in soft agar and is tumorigenic in SCID mice.
Conclusions: This new cell line, UKE-1, appears to combine hematopoietic and endothelial features, indicating the close ontogenic relation of both lineages.
Copyright 2000 American Cancer Society.