Therefore, while the knockdown of CAP1 in HeLa and metastatic breast cancer cells reduces the rate of actin filament turnover, it causes the activation of FAK, and possibly also altered Rap1 signaling, which not only promotes cell adhesion and turnover of focal adhesions, but may also promote lamellipodia formation to promote cell motility and invasiveness. Here, PTK2 is linked to breast carcinoma.