Overproduction of transforming growth factor-β1 (TGF-β1) by injured tubular epithelial cells is a key element in the development of renal fibrosis after renal insults; this is known because tubular atrophy and fibrosis can be ameliorated by targeting TGF-β signaling by using neutralizing antibodies to block TGF-β or anti-TGF-β type II receptors [58,59]. Here, TGFB1 is linked to renal fibrosis.