Since chronic AOPP administration raised the expression of transforming growth factor beta 1 (TGF-β1), a well-documented fibrogenic growth factor, there was a direct connection between the AOPP and the pathogenesis of nephritic inflammation and fibrosis, which is one of the key mechanisms of kidney deterioration in patients with BEN [48]. This evidence concerns the gene TGFB1 and Balkan nephropathy.