IGF1 and liver dysplastic nodule: Diverse factors have been reported to induce aberrant expression of p21 in MCs and experimental DN, including HG [9, 18], insulin-like-growth-factor-1 (IGF-1) [9, 19], transforming growth factor-β1 (TGF-β1) [6, 10], connective tissue growth factor (CTGF) [20], advanced glycation end products (AGEs), and their receptors (RAGE) [6].