MDH2 and breast cancer: Functional enrichment analysis of differential genera identified 19 MetaCyc signaling pathways in which 12 are significantly enriched in BC group by containing 165 genes.Then top-ranked 10 bKGs (mdh, pykF, gapA, zwf, pgi, tpiA, pgk, pfkA, ppsA, and pykA) were selected as the targets of candidate drugs through protein-protein interaction (PPI) network analysis.