Regulatory chemicals or proteins produced by specific cells or tissues (e.g., cells in the developing nervous system) that stimulate cellular growth, differentiation, or tissue development. Sometimes the term ‘growth factor’ is used interchangeably with ‘cytokine’, with cytokine denoting a neutral term that does not indicate what is being signalled. One example of a growth factor is nerve growth factor, which stimulates the outgrowth of nerve fibers during the differentiation of neurons. Growth factors occur naturally in the body, but can be also manufactured and used as drugs.
See Cytokines, Differentiation (embryology), Fibroblast growth factor (FGF), Nerve growth factor (NGF), Morphogenesis, Polypeptides, Tyrosine kinase receptor/pathway