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Anna Bafico coauthored a mechanistic classification of growth factors and their receptors. The account treats a growth-factor family as a collection of related signal molecules with distinguishable receptor interactions, rather than as a single interchangeable stimulus.^[ref]

For example, related growth-factor chains can assemble into different dimers. Their receptor recognition and target-cell context help determine the biological response. This provides a useful bridge between protein structure, signal transduction and the regulation of cell proliferation.

PDGF means platelet-derived growth factor, a family of signaling protein ligands for PDGFR. Members form protein dimers, including the classical AA, AB and BB combinations.^[ref] Ligand binding can bring two receptors together and activate their receptor tyrosine kinase activity.^[ref]

Release from platelets links PDGF to local tissue responses after injury. Nearby connective-tissue cells can respond by entering cell proliferation.^[ref]

Stuart A. Aaronson studies the connection between growth factors, their receptors and cancer. His coauthored account of growth-factor families distinguishes extracellular signal molecules from the receptors that recognize them and transmit signals into a cell. The distinction explains how an alteration of a receptor can change proliferation even without an increase in its ligand.^[ref]

The scientific connection is between normal growth regulation and oncogene action: a signaling pathway that normally responds to tissue needs can contribute to inappropriate cell growth when its control is disrupted.