Since Ozcan et al. reported PAX8 nuclear expression in atrophic renal tubular epithelial cells regardless of nephronic segments [12,13], we considered an opportunity to investigate relationship of PAX8 nuclear positivity in the epithelial structures of the human adult kidney affected with various chronic diseases clinically presented with proteinuria, as well as to compare it with expression pattern in patients with acute kidney injury and to assess the clinical relevance of PAX8 detection in kidney biopsies. This evidence concerns the gene PAX8 and acute kidney injury.