In T2DM-MCI patients, plasma HSP27 levels were decreased, and the risk of MCI development was significantly increased when HSP27 levels were below 3.51 pg/mL (OR = 0.355), with a specificity as high as 94.4%, suggesting that HSP27 is expected to be a biomarker for diabetic nerve-related lesions. This evidence concerns the gene HSPB1 and type 2 diabetes mellitus.