Bevacizumab reduced the ability of invasion in C4-2B (b), comparing with an equal amount of IgG treatment (a). In the invasion assay, we seeded cells on the top of the Matrigel and added VEGF to the lower chamber. Invasive cells penetrate Matrigel and end up on the other side of the Matrigel. We estimated invasion by measuring the fluoresence intensity in the fluorescence microplate reader and counting the number of invading cells, and setting the average of invading cell numbers of C4-2B with VEGF added to the lower chamber as 100%. The results showed that VEGF-mediated invasion of C4-2B was suppressed by bevacizumab, and not by IgG1. (P < 0.01, Figure 4c).