PTK2 and colon carcinoma: To definitively link the upregulation of FAK/PYK2/p-GSK3α/βY279/Y216/β-catenin axis in human CRC to the loss of functional APC, we analyzed serial sections of colon specimens from a patient with FAP, an inherited colorectal cancer syndrome caused by germline mutation of APC. The levels of FAK/PYK2, p-GSK3α/βY279/Y216 and β-catenin were all found substantially elevated in colon carcinomas (Figure 6D), thus providing proof-of-concept evidence linking these molecular changes to the loss of functional APC in CRC patients.