NCIt definition : Mitogenic factors with high affinity for heparin. These proteins regulate the proliferation
and differentiation of mesenchymal, epithelial, and neuroectodermal cells. Heparin-binding
may sequester these proteins in the extracellular matrix, or increase the stability
of these growth factors. Heparin may enhance the activity of some family members,
as it may be required for their interactions with cellular receptors.;