We collected 47 classic variants of PTC, 9 hobnail variants of PTC, 3 anaplastic thyroid cancers (ATC), and 10 medullary thyroid cancers (MTC) to evaluate the differences in NR3C2 gene expression among aggressive thyroid cancers. The gene discussed is NR3C2; the disease is thyroid gland undifferentiated (anaplastic) carcinoma.