Epidermal Growth Factor as a Biological Switch in Hair Growth Cycle

The study demonstrated that Epidermal Growth Factor (EGF) played a crucial role as a biological switch in the hair growth cycle, particularly in the transition between anagen (growth phase) and catagen (regression phase). Continuous EGF expression in transgenic mice arrested hair follicle development, indicating that EGF signaling through EGFR/ErbB2 was essential for initiating hair growth. Inhibitors of EGFR and ErbB2 halted hair growth in wild-type mice but not in transgenic mice. Breeding experiments with waved-2 mice, which have lower EGFR activity, rescued the hair phenotype, confirming the role of EGF. The findings suggested that manipulating EGF signaling could offer therapeutic approaches for treating conditions like abnormally thin hair or unwanted hair growth.