Overview

A growth factor is a naturally occurring molecule—typically a protein or peptide—that instructs cells to divide, differentiate, survive, migrate or die. Growth factors act as local or systemic signals that coordinate complex processes such as embryonic development, tissue maintenance and wound repair. Although often produced by one cell type to affect neighboring cells, some act on the same cell that made them (autocrine) or travel through the bloodstream to distant targets (endocrine).

Characteristics and mechanisms

Most growth factors bind to specific cell-surface receptors and trigger intracellular signaling cascades. Common receptor types include receptor tyrosine kinases (RTKs), serine/threonine kinase receptors and cytokine receptors that activate JAK–STAT pathways. Downstream signaling pathways frequently engaged are MAP kinase (MAPK), PI3K–AKT and SMAD pathways. The cellular response depends on receptor expression, ligand concentration, and the cell’s developmental context.

Major types and examples

  • Fibroblast growth factors (FGFs) — roles in angiogenesis, development and wound healing.
  • Vascular endothelial growth factor (VEGF) — promotes blood vessel formation.
  • Epidermal growth factor (EGF) — stimulates epithelial cell proliferation.
  • Platelet-derived growth factor (PDGF) — involved in wound repair and mesenchymal cell growth.
  • Transforming growth factor beta (TGF-β) — regulates differentiation and immune responses.
  • Insulin-like growth factors (IGFs) — mediate effects of growth hormone and influence growth and metabolism.
  • Colony-stimulating factors (e.g., G-CSF) and erythropoietin (EPO) — stimulate blood cell production.

Biological and clinical importance

Growth factors are essential for normal physiology: they shape organogenesis in embryos, maintain stem cell niches, and drive repair after injury. Clinically, recombinant growth factors are used to treat conditions such as anemia (EPO) and neutropenia (G-CSF), and PDGF-containing products have applications in tissue engineering. Conversely, dysregulated growth factor signalling contributes to diseases—overactivity can promote cancer, excessive angiogenesis, or fibrosis; insufficient signalling impairs healing.

History and therapeutic targeting

Key discoveries in the mid-20th century identified molecules that promote cell growth, including nerve growth factor and epidermal growth factor; these advances established the concept of protein growth factors and earned recognition in physiology research. In medicine, targeting growth factor pathways has become a major approach: monoclonal antibodies and small-molecule inhibitors can block receptors (for example, anti-EGFR or anti-VEGF therapies) to treat cancers and other disorders driven by abnormal signalling.

Distinctions and notable facts

The term "growth factor" overlaps with cytokines and hormones but generally refers to proteins that modulate cellular growth, differentiation or survival in a paracrine or autocrine manner. Growth factors may be soluble or tethered to the cell membrane and frequently work in combination—cells integrate multiple signals to generate a coordinated response. Therapeutic use requires careful control because stimulating growth pathways can have unintended proliferative or oncogenic effects.

Summary: Growth factors are central regulators in biology and medicine; they enable development and regeneration but can also drive disease when signalling becomes dysregulated.