Growing studies showed that biomarkers based on renal tubules can early reveal the renal structure and dysfunction of diabetes patients and better monitor the progress of DN and judge the prognosis, such as kidney injury molecule-1(KIM-1), β2-microglobulin (B2M), N-acetyl-β-D-glucosaminidase (NAG), osteopontin (OPN), etc. KIM-1, a transmembrane glycoprotein of proximal tubular epithelial cells of the kidney, cannot be detected when the kidney is structurally or functionally normal, but it can be significantly upregulated with tubular damage. Here, B2M is linked to diabetes mellitus.