DKK3 and chronic kidney disease: Although the clinical value of DKK3 urinary measurements for the determination of tubular atrophy and interstitial fibrosis has to be corroborated in larger and ethnically divergent patient cohorts, we are convinced that a non-invasive urinary biomarker for chronic tubulointerstitial damage, relating to prognosis and course of the chronic renal disease, has been detected.