CDC42 and breast cancer: The proposal that WNT‐5A increases breast cancer cell migration is compatible with its capacity to increase Cdc42 activity in fibroblasts (Schlessinger et al., 2007) and non‐tumorigenic breast epithelial cells (Dejmek et al., 2006), since Cdc42 activity is commonly associated with increased cell migration (Fritz et al., 1999; Karlsson et al., 2009; Tang et al., 2008).