Interestingly, the MMP-9 gene, encoding matrix metalloproteinase-9, which is associated with inflammatory processes and plays an important role in A. hydrophila-related diseases49, was also identified in this study as a DEG after A. hydrophila stimulation, and was mapped to three KEGG pathways, cancer, bladder cancer, and leukocyte transendothelial migration. The gene discussed is MMP9; the disease is urinary bladder carcinoma.