The integrative analysis of the bioinformatics and ML identified 10 potent MDD-related biomarkers including CEACAM8, CLEC12B, DEFA4, HP, LCN2, NRG1, OLFM4, SERPING1, TCN1 and THBS1, that showed the most significant and strong differential expression between MDD patients and HCs. Here, LCN2 is linked to major depressive disorder.