EGFR and skin squamous cell carcinoma: As the inhibition of the EGFR–ERK pathway is important for the treatment of skin disorders, such as psoriasis and cSCC, further research on mechanisms underlying the inhibition of EGFR–ERK signaling by SPE may lead to the development of therapeutic agents for more effective treatments against skin diseases characterized by abnormalities in the EGFR–ERK signaling pathway.