PTK2 and melanoma: AKT1E17K expression in melanoma cells increased invasion, and this was reduced by pharmacological inhibition of either AKT or focal adhesion kinase (FAK) in vitro.5 FAK is a non-receptor tyrosine kinase that promotes cancer cell motility and has also been implicated in promoting cell proliferation, invasion, and metastasis (reviewed by Chuang et al9).