Pairwise comparisons in PAI-1 mRNA level show lower expression of PAI-1 mRNA in incipient DN group (p = 0.011) and DM group (p = 0.003) compared to control, while there were no significant differences in PAI-1 mRNA expression level between overt DN group and incipient DN group (p = 0.963), overt DN group and DM group (p = 0.184), overt DN group and control (p = 0.089), and incipient DN group and DM group (p = 0.219). The gene discussed is SERPINE1; the disease is diabetes mellitus.