In DN, chronic hyperglycaemia plays a pivotal role via activation of several mechanisms, such as increasing TGF‐β expression, overproducing mesangial matrix and protein kinase C activation, which cause mesangial expansion via TGF‐β, vascular endothelial growth factor, ROS and angiotensin II. The gene discussed is TGFB1; the disease is liver dysplastic nodule.