We then conducted correlation analysis between the expression levels of the top 10 potential hub genes and the level of HbA1c of all samples and confirmed SERPINF1, MEDAG, IL33, and IL24 as four real hub genes of T2DM and validated the conclusion with two external GEO datasets (GSE38642 and GSE50397). This evidence concerns the gene SERPINF1 and type 2 diabetes mellitus.