PTK2 and osteosarcoma: The current study showed that the CXCL1 could signal the CXCR2/focal adhesion kinase (FAK)/phosphatidylinositol-3-kinase (PI3K)/Akt/nuclear factor-kappa B (NF-κB) pathway to increase VCAM-1 expression and subsequently upregulate the metastasis ability of human osteosarcoma cells.