PTK2 and oral cavity squamous cell carcinoma: Liu et al. [ 10] demonstrated a strong association between PXN and invasiveness and metastases of gallbladder squamous cell/ adenosquamous carcinoma and adenocarcinoma and concluded that PXN overexpression has a significant role in clinical behavior and poor prognosis of these tumors.In a recent in vitro study, Song et al. [ 8] also investigated the abnormal expression of FAK and PXN and their correlation with the invasion and metastasis in oral squamous cell carcinoma (OSCC) cell line SCC-5.