Pak1 is required for KIF5B‐mediated transport of a large WAVE2 protein complex toward membrane protrusions in response to hepatocyte growth factor in breast cancer cells.11, 36 Also, stathmin/Op18 is associated with hepatocyte growth factor‐induced WAVE2 transport to membranes and the formation of cell protrusions.37 The WAVE2‐Arp2/3 complex induces the nucleation of actin assembly, thereby leading to the formation of cell protrusions.5, 38 Thus, WAVE2 is involved in protrusion formation and promotes cell motility and invasion. This evidence concerns the gene STMN1 and breast cancer.