AXL and neoplasm: There are several lines of evidence that AXL is involved in tumor metastatic processes, such as cell migration and invasion [13, 52], and we confirmed that DS-1205b inhibited hGAS6-dependent cell migration in vitro. In the NIH3T3-AXL xenograft model, DS-1205b showed a potent tumor growth-inhibitory effect in vivo. This result strongly suggested that DS-1205b clearly inhibits AXL function in vivo when it is systemically administered.