As shown in Figure 5A and 5B, metastatic gastric cancer cell supernatant treatment significantly downregulated E-cadherin expression in peritoneal mesothelial cells, while it notably upregulated N-cadherin, α-SMA, Snail, Twist, Slug, Cyclin D1, MMP3 and MMP9 expression. The gene discussed is MMP9; the disease is gastric cancer.