HGF and head and neck squamous cell carcinoma: Activation of Met by HGF in HNSCC cells leads to activation of Erk and Akt kinases, and Ets-related transcription factor E1AF activation, which in turn results in up-regulation of urokinase-type plasminogen activator and matrix metalloproteinases (MMP-1, 3 and 9) production [94,102].