CCN2 and liver dysplastic nodule: The renin-angiotensin-aldosterone system (RAAS), the formation of advanced glycosylation end products (AGE), activation of transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), protein kinase C (PKC), mitogen-activated protein kinases (MAPKs) and reactive oxygen species (ROS) are some of the important pathways in the development of DN.