What Is Keratinocyte Growth Factor? Definition and What Research Reports

Keratinocyte growth factor (KGF) is a signalling protein — formally fibroblast growth factor 7 (FGF7) — that belongs to the fibroblast growth factor family. It is produced mainly by cells of mesenchymal origin, such as dermal fibroblasts and stromal cells, and it acts in a paracrine fashion on neighbouring epithelial cells, which carry its receptor (the IIIb splice variant of FGFR2, often written FGFR2b). Because the receptor is largely restricted to epithelium, KGF is usually described in the literature as an epithelium-selective growth factor rather than a general mitogen. A review of the molecule summarised its identification, receptor biology and its development as a recombinant protein for epithelial injury settings (Expert Opinion on Biological Therapy, 2009). This page is for educational purposes only and is not medical advice; consult a licensed physician for any health decision.

What class of molecule is it?

KGF is a protein growth factor, not a small peptide fragment. Full-length human FGF7 is roughly 190 amino acids in its precursor form and is secreted with a signal sequence; the mature protein is a single-chain polypeptide that binds heparan sulfate as part of receptor engagement. Because it is a full protein, research-grade material is generally made recombinantly rather than by solid-phase synthesis. One protein-expression study described a process for high-level production of keratinocyte growth factor 2 in Escherichia coli, a detail that illustrates how these molecules are manufactured for laboratory work (Protein Expression and Purification, 2023).

KGF-1 versus KGF-2

Two related family members appear in the literature under the KGF label. KGF-1 is FGF7. KGF-2 is FGF10; it signals through the same FGFR2b receptor and is frequently studied in overlapping epithelial contexts. Papers usually specify which one was used, and readers comparing studies should note that the two are distinct proteins with distinct reagents. A 2021 study of KGF-2 in ultraviolet-B-exposed skin models reported that the growth factor acted via the AhR/Nrf2 signalling pathway (Frontiers in Pharmacology, 2021).

How the term is used in peptide research

In peptide and protein research writing, "keratinocyte growth factor" is used in three broad ways. First, as a gene or protein marker: studies measure whether KGF and its receptor are expressed more or less in a diseased tissue than in healthy tissue. Second, as an administered recombinant protein in animal or cell models, where investigators give KGF and observe an epithelial endpoint. Third, as a delivery-formulation payload, where the protein is coupled to a carrier to change how long it stays at a target site.

An example of the marker usage is an immunohistochemistry study of oral lichen planus tissue, which examined the expression of keratinocyte growth factor and its receptor in that lesion compared with control tissue (International Journal of Clinical and Experimental Pathology, 2018). An example of the formulation usage is a materials-science study in which fibrin nanoparticles were coupled with keratinocyte growth factor and researchers reported an enhanced dermal wound-healing rate in the model used (ACS Applied Materials & Interfaces, 2019). KGF is also described as an intermediary in other signalling systems: one study reported that dexamethasone promoted keratinocyte proliferation by triggering keratinocyte growth factor in mast cells (International Archives of Allergy and Immunology, 2019).

What the published literature reports

The published work on KGF clusters around epithelial tissues that have been injured by radiation, drugs or irritants. The findings below are what the individual papers reported in their own models; they are laboratory and animal results, and this page does not extend them to any human use.

Salivary gland and radiation models

Two mouse studies examined KGF-1 in the context of irradiation. A 2017 study reported radioprotective effects of keratinocyte growth factor-1 against irradiation-induced salivary gland hypofunction in its mouse model (Oncotarget, 2017). A follow-up study reported that keratinocyte growth factor-1 protected against radioiodine-induced salivary gland dysfunction in mice (International Journal of Environmental Research and Public Health, 2020). Both were preclinical; neither establishes an outcome in people.

Mucosal and intestinal barrier models

Researchers have also studied KGF where epithelial barriers are damaged by drug treatment. One mouse study reported that keratinocyte growth factor ameliorated mycophenolate mofetil-induced intestinal barrier disruption (Molecular Immunology, 2020). In an engineered tissue system, a 2024 study reported that recombinant human keratinocyte growth factor ameliorated cancer-treatment-induced oral mucositis on an organ-on-a-chip platform (Advanced Healthcare Materials, 2024).

Lung and airway models

Airway epithelium is another recurring setting. A rat study reported that keratinocyte growth factor improved alterations of lung permeability and bronchial epithelium in an allergic model (European Respiratory Journal, 2007). In preterm pigs undergoing mechanical ventilation, the study reported that intratracheal keratinocyte growth factor enhanced surfactant protein B expression (Frontiers in Pediatrics, 2021).

Safety and Tolerability: What Studies Report

The verified literature summarised here is largely preclinical and mechanistic, and the individual reports cited above focus on efficacy endpoints in animal, tissue-chip and expression models rather than on structured adverse-event tabulation. The 2009 review article discussed keratinocyte growth factor as a biological therapy, including its development and the considerations that accompany a mitogenic protein acting on epithelial tissue (Expert Opinion on Biological Therapy, 2009). Because KGF drives epithelial proliferation, researchers discussing it typically address the biological questions that follow from stimulating cell division in tissue. No dosing information is presented on this page, and none of the studies cited should be read as describing a regimen for people.

Limitations to keep in mind

• Most of the findings above come from mice, rats, pigs or engineered tissue systems; species and model differences limit how far results generalise.
• "KGF" in a paper title may mean FGF7 or FGF10 — the two are different proteins and are not interchangeable in interpretation.
• Formulation matters: a study delivering KGF on fibrin nanoparticles (ACS Applied Materials & Interfaces, 2019) is not directly comparable to an intratracheal instillation study (Frontiers in Pediatrics, 2021).
• Expression studies, such as the oral lichen planus analysis (International Journal of Clinical and Experimental Pathology, 2018), describe association, not causation.
• Recombinant protein quality and production method vary between laboratories (Protein Expression and Purification, 2023).

References

• Keratinocyte growth factor (Expert Opinion on Biological Therapy, 2009)
• Keratinocyte Growth Factor-1 Protects Radioiodine-Induced Salivary Gland Dysfunction in Mice (International Journal of Environmental Research and Public Health, 2020)
• Radioprotective effects of Keratinocyte Growth Factor-1 against irradiation-induced salivary gland hypofunction (Oncotarget, 2017)
• Keratinocyte growth factor ameliorates mycophenolate mofetil-induced intestinal barrier disruption in mice (Molecular Immunology, 2020)
• Fibrin Nanoparticles Coupled with Keratinocyte Growth Factor Enhance the Dermal Wound-Healing Rate (ACS Applied Materials & Interfaces, 2019)
• Intratracheal Keratinocyte Growth Factor Enhances Surfactant Protein B Expression in Mechanically Ventilated Preterm Pigs (Frontiers in Pediatrics, 2021)
• Keratinocyte Growth Factor 2 Ameliorates UVB-Induced Skin Damage via Activating the AhR/Nrf2 Signaling Pathway (Frontiers in Pharmacology, 2021)
• Expression of keratinocyte growth factor and its receptor in oral lichen planus (International Journal of Clinical and Experimental Pathology, 2018)
• High-level production of keratinocyte growth factor 2 in Escherichia coli (Protein Expression and Purification, 2023)
• Keratinocyte growth factor improves alterations of lung permeability and bronchial epithelium in allergic rats (European Respiratory Journal, 2007)
• Dexamethasone Promotes Keratinocyte Proliferation by Triggering Keratinocyte Growth Factor in Mast Cells (International Archives of Allergy and Immunology, 2019)
• Recombinant Human Keratinocyte Growth Factor Ameliorates Cancer Treatment-Induced Oral Mucositis on a Chip (Advanced Healthcare Materials, 2024)