In fact, the HIF-1α protein was differentially expressed in primary thyroid cancers associated with advanced stage; its expression was supressed in normal thyroid tissue and was highest in the most aggressive dedifferentiated anaplastic thyroid carcinomas (ATCs) (Hanada, Feng & Hemmings, 2004), supporting its role for thyroid tumor aggressiveness, progression as well as metastasis. This evidence concerns the gene HIF1A and thyroid tumor.