Because in other tumor models FAK is required for PI3K- and Ras-dependent tumorigenesis [30] and the integrins/FAK complex activates Ras signaling to MAPK [31], [32] a plausible mechanism by which IGF-I promotes migration and invasion of bladder cancer cells would be by activating FAK and the signaling cascade leading to Akt, MAPK and paxillin activation. This evidence concerns the gene PTK2 and urinary bladder carcinoma.