Recent studies have found that overexpression of ARG2 is a poor prognostic factor in a variety of cancer types, including pancreatic cancer 57, thyroid tumors 58, gastric cancer 59, neuroblastoma 60, 61, head and neck squamous cell carcinoma 62, and acute myeloid leukemia (AML) 63. This evidence concerns the gene ARG2 and thyroid tumor.