COL1A2 and Proteinuria: Besides, compared to the subnephrotic proteinuria group, COL1A2 mRNA expression was significantly higher in the nephrotic proteinuria group (P = 0.0075), and the mRNA expression levels of ACTN1, PRKCB, ITGB2, HLA-DPA1, and HLA-B in kidney tubules were positively correlated with proteinuria in patients with DN (Figure 9(b)).