Examples of biomarkers are proteins, lipids, microRNAs, genomic, etc. Plenty of biomarkers associated with DKD were found in recent years, such as serum cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-β-D-glucosaminidase (NAG), and serum homocysteine (Hcy) [12]. The gene discussed is LCN2; the disease is diabetic kidney disease.