The crucial role of integrins in cancer cell invasion is additionally evidenced by an α5β1 integrin-FN interaction (Figure 1C), which accelerates cell invasion of SiHa cervical cancer cells and promotes the expression and activation of pro-MMP-9, as well as moderate change of pro-MMP-2 activity through the FAK, ILK, ERK, PI3K and NF-κB signaling cascade [58]. Here, PTK2 is linked to cancer.