Yamaguchi et al. reported the effect of EGF on the activation of RAS/RAF/MEK/ERK pathway, also known as MAPK/ERK pathway and they found that EGF stimulated the phosphorylation of Raf and ERK in primary cultures made of human ADPKD but could not stimulate the phosphorylation in normal kidney cell. Here, EGF is linked to autosomal dominant polycystic kidney disease.