To determine whether MET is involved in MSLN-regulated tumor cell penetration of the BBB, we knocked down MET in PC9-BrM cells with siRNA (Fig. 4F) and then overexpressed MSLN in PC9-BrM cells in which we had previously knocked down MSLN (PC9-BrM-SH2) (Fig. 4G). This evidence concerns the gene MET and neoplasm.