Subsequently, more and more human cancers have been suggested to display high Ecto-5′-nucleotidase expression, such as lung cancer [16,17], breast cancer [18], colorectal cancer [19,20], pancreatic cancer [21], gallbladder cancer [22], prostate cancer [23,24], thyroid cancer [25], and head and neck cancer [26]. The gene discussed is NT5E; the disease is thyroid cancer.