Figure 6. Peritoneal mesothelial cells significantly enhanced the proliferation of gastric cancer cells. (A) Primary or metastatic gastric cancer cells were co-cultured with HMrSV5 cells or nothing. (B) The viability of gastric cancer cells after 72 h of incubation was evaluated with a CCK-8 assay. (C–F) The relative protein expressions of MMP3, MMP9 and PCNA in primary or metastatic gastric cancer cells were detected by western blot. **P<0.01.