The prognostic value of Ecto-5′-nucleotidase expression was estimated in many kinds of human tumor including gastric cancer [11,12], lung cancer [16,17], gallbladder cancer [22], prostate cancer [23], head and neck cancer [26,31,32,33], breast cancer [34,35], colorectal cancer [36], melanoma [37], ovarian cancer [38] and so on. The gene discussed is NT5E; the disease is head and neck cancer.