MMP9 and bronchopulmonary dysplasia: Figure 5E demonstrates that the SVM-RFE analysis obtained 6 DENRGs as reliable molecular biomarkers for BPD. In BPD, 5 DENRGs were identified: matrix metallopeptidase 9 (MMP9), sialic acid binding Ig-like lectin 5 (Siglec-5), dysferlin (DYSF), maltase-glucoamylase (MGAM), and S100 calcium-binding protein A12 (S100A12). All biomarkers were found to be upregulated in BPD patients (Figure 5F).