Members of the EGF receptor family in normal and pathological epidermis.

Epidermal growth factor (EGF) and analogs bind to transmembrane receptors that exhibit tyrosine kinase activity in their cytoplasmic domain and which belong to the EGF receptor family. These growth factors and relevant receptors were named after initial identification of the functions of their founding members in the epidermis. However, since the EGF receptor was recognized as an oncogene, it has been mainly analyzed in cancer; the members of the receptor's family were also found and characterized initially in tumors and cancer cells. The present article reviews mainly the expression and function of EGF receptor family members in normal epidermis, together with the expression and function of their respective ligands, and we extend the review to potential involvement of these systems in epidermal disease.