In the STZ-induced diabetic mouse model, DNA synthesis increases and peaks at day 2 in the proximal tubules, and the expression of various growth factors including epidermal growth factor (EGF), platelet-derived growth factor (PDGF), basic fibroblast growth factor (FGF), insulin-like growth factor-1 (IGF-1), hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) has been observed (8).Together, they lead to proliferation of renal tubular cells during the early stage of DKD. The gene discussed is EGF; the disease is diabetic kidney disease.