With respect to the role of SMAD4 in head and neck squamous cell carcinoma (HNSCC), including OSCC, it has been reported that the loss of SMAD4 causes spontaneous HNSCC in a mouse model 10, and that the loss of SMAD4 proteins is also observed in clinical OSCC 10, 11. The gene discussed is SMAD4; the disease is head and neck squamous cell carcinoma.