Growth Factor is a protein molecule made by the body; it functions to regulate cell division & cell survival. Growth factors can also be produced by genetic engineering in the laboratory and used in biological therapy. Growth factors bind to receptors on the cell surface, with the result of activating cellular proliferation and/or differentiation. Growth factors are quite versatile, stimulating cellular division in numerous different cell types; while others are specific to a particular cell-type. Growth factors are proteins that promote cell growth.