AREG and psoriasis: Although the precise mechanism of hyperproliferation in psoriasis is still unclear, several growth factors and cytokines, such as epidermal growth factor (EGF), amphiregulin, epiregulin, IL-6, and IL-8, are assumed to be important.[1] Furthermore, it is supposed that TNF-α and INF-α, which are derived from dendritic cells and T cells, regulate the expression of these growth factors and cytokines.