CDC42 and breast carcinoma: The increased migratory and invasive capacity of the Cdc42-overexpressing MECs suggests that Cdc42 overexpression may facilitate mammary tumor cell invasion and metastasis in vivo, and indeed, studies investigating the effects of Cdc42 knockdown in breast cancer xenografts have shown that Cdc42 regulates tumor cell invasion and metastasis in vivo[49].