THE BINDING OF ACUTE MYELOID-LEUKEMIA BLAST CELLS TO HUMAN ENDOTHELIUM

AML blast cell adhesion to endothelium is in all likelihood a prerequi site for blast cell migration across the vascular wall in the peripher y and the subsequent establishment of leukemic extravascular disease. A general feature of malignant cells is their acquisition of altered o r aberrant adhesive capabilities which appear to be associated with th eir ability to metastasize. Aberrant expression of integrin adhesion m olecules and of membrane oligosaccharide structures is found in AML an d various solid tumors. With respect to AML, these alterations in adhe sive phenotype may confer a proliferative advantage on the malignant c ells in the marrow, may facilitate egress from the bone marrow into th e peripheral vasculature and may enable AML blast cells to traverse th e vessel wall and so establish extravascular disease. Oncogenes may be directly involved in the acquisition of such aberrant adhesive phenot ypes. Neutrophil extravasation is described as a model for leukocyte m igration across the vessel wall and brief summaries of experimental wo rk involving aspects of AML blast cell and normal CD34+ bone marrow ce ll adhesion to endothelium in vitro are described.