TSPAN9 and gastric cancer: Previous research indicates that TSPAN9 has the potential to inhibit the migratory and invasive capabilities of gastric cancer SGC7901 cells via decreasing matrix metalloproteinase-9 (MMP-9) and urokinase-type plasminogen activator (uPA) secretion through extracellular signal-regulated kinases 1 and 2 (ERK1/2) pathway (44).