Real-time imaging revealed that 10 nM of rC5a enhanced the total distance that the NUGC3/C5aR cells moved in Matrigel (Figure 3D and 3E) and that W-54011 suppressed the mobility of NUGC3/C5aR cells (Figure 3F and 3G).These results indicate that the C5a-C5aR signal enhances the invasion and mobility of GC cells in vitro. This evidence concerns the gene C5AR1 and gastric cancer.