TGFB1 and head and neck cancer: These previous studies suggest a strong association between TGF-β1 and TGF-βR1 functional genetic variants and the prognosis of patients with smoking-related head and neck cancer, which supports our results and indicates the potential of TGF-β1 and TGF-βR1 to be a key factor in predicting patient’s treatment responsiveness and the prognosis of our studied patients.