RAC1 and cancer: Therefore, the fact that NDV replication requires Rac1 for tropism in human cancer cells [36], as well as the role of Rac1 in cell migration [60] and actin reorganisation [76], the rearrangement of actin cytoskeletons in syncytium cells (Figure 4(d)) and the repressed mobility of NDV-treated GBM cells observed in the live cell video have placed Rac1 in NDV tropism in GBM.