To the Editor: Diabetic kidney disease (DKD) is the most common cause of end?stage renal disease (ESRD); however, the onset of DKD is difficult to detect.[1] When persistent microalbuminuria becomes detectable, DKD has already progressed to the third disease stage, and finding biomarkers that are more sensitive than microalbuminuria is therefore necessary to indicate kidney damage at an earlier stage of DKD.[2] Both glomerular and tubulointerstitial damages have been repeatedly demonstrated to be important factors in the pathophysiology of DKD.[3] Therefore, we investigated the expression levels of six markers closely related to the glomerulus and renal tubule.