Objective:In vitro studies have shown that KGF-2 has a proliferative effect on neonatal foreskin keratinocytes. Cells from adult donors have been shown to respond to KGF-1 to a lesser degree than neonatal keratinocytes. The purpose of the study was to investigate the proliferative effect of KGF-2 on keratinocytes from an adult subject. Methods: Standard medium was Keratinocyte Growth Medium without BPE, hydrocortisone and EGF. Keratinocytes cultured from a 48-year-old subject were seeded at 2 104 in 32 mm dishes in standard medium with EGF.After 24 hours, medium was changed to standard medium with KGF-2 at 4, 16, 125 and 500 ng/ml or without KGF-2. Standard medium with EGF was used as a positive control. The growth of keratinocytes was monitored by the MTT assay and by photographs at day 3, 5 and 7. Each treatment was performed in triplicate. Results: KGF-2concentrations from 4 to 500 ng/ml all showed a significant proliferative effect on days 5 to 7 compared to the negative control (P＜ 0.01). By day 3 the response of keratinocytes in KGF-2 was 1.5 to 2.5-fold, by day 5 was 3 to 5-fold and by day 7 was 3 to 12-fold relative to the negative control. The optimal response was in 125 ng/ml KGF-2 at day 7. Cell proliferation was also consistently higher in all KGF-2 concentrations compared to the positive control.Conclusion: KGF-2 exerted a significant effect on the proliferation of adult keratinocytes, which was higher than that of the EGF concentration in the growth medium. This supports the clinical work where KGF-2 has been shown to improve the healing in chronic wounds in adults.