Figure 7. Gene expression analysis and PCR validation. (A) Expression analysis of the four model genes in the GSE30122 cohort, showing down-regulation in DN samples. (B–E) PCR validation results confirming the reduced expression levels of VEGFA, MAGI2, THSD7A, and ANKRD28 in DN compared to control blood samples, supporting their potential as diagnostic biomarkers. (*p < 0.05, ***p < 0.001).