Furthermore, there are close relationships between gene expression profile detected in main components of the solid cell nests (such as oncofetal fibronectin, p63, Carcinoembryonic antigen (CEA), and Cytokeratin 34 beta E12 (CK34bE12) and some thyroid malignancies, suggesting that such undifferentiated remnant embryonic stem cells may be the niche for thyroid cell survival, and may play an important stem cell-like role in the origin of several thyroid disorders, including TC [39,40]. Here, CEACAM5 is linked to thyroid gland disorder.