Platelet-derived growth factor and its receptor in blood cell differentiation and neoplasia.

Platelet-derived growth factor (PDGF) is a family of dimeric protein molecules synthesized by differentiated, non-dividing and proliferating blood cells. Experimental findings indicate that PDGF is involved in development and/or maintenance of physiological functions of certain normal blood cells. Also, PDGF synthesis correlates with certain blood cell proliferative diseases caused either spontaneously or associated with viral infection. There is increasing evidence that the diverse effects of PDGF in both normal and abnormal physiological functions of blood cells may be regulated at the level of its receptor. New experimental findings are discussed relating to PDGF receptors in normal leukemic, and virally-infected human cells of myeloid and lymphocytic lineages. At specific developmental stages this regulation may take the form of PDGF and its receptor being expressed or co-expressed; the unmodified or modified form of receptor that specifically interacts with PDGF; the cellular site at which the PDGF-receptor interacts with its ligand; and co-expression of the PDGF-receptor with other receptors associated with specific cell lineage or functions. Elucidation of events involved in synthesis, processing, and interactions of PDGF isoforms and their respective receptors will enable us to develop pharmacological means that may either interfere with, or enhance these desired blood cell functions. This review focuses on PDGF and its receptor in human blood cell differentiation and neoplasia.