PAK1 and cervical squamous intraepithelial neoplasia: Whether reduction of Pak1/2 activity can lead to increased tumour aggressiveness remains to be addressed, but as the function of Pak1/2 downstream of Tiam1 is kinase dependent (Fig. 6), a consideration for any future Pak inhibitor trials is that treatment could lead to mitotic defects and potentially CIN through the pathway we have identified.