In the renal tubular interstitial region, microarray analysis identified several JAK/STAT family members with downregulated expression in patients with early diabetic nephropathy, whereas most JAK/STAT family members such as JAK1, JAK2, JAK3, STAT1, STAT3, STAT4, and STAT5B were upregulated in patients with progressive diabetic nephropathy compared with controls. This evidence concerns the gene STAT3 and diabetic kidney disease.