PTK2 and chondrosarcoma: reported that CTGF increased the activity of focal adhesion kinase (FAK), mitogen-activated protein kinase kinase (MEK), and ERK proteins (143), which is consistent with the findings of Tan and colleagues that CTGF promotes chondrosarcoma cell migration by increasing the expression of MMP-13 via the αvβ3 integrin, FAK, ERK, and NF-κB signal pathways (144).