HSPA9 and medullary thyroid gland carcinoma: In addition, it was revealed by immunohistochemistry that mortalin was increased in human MTC, PTC, FTC, and ATC compared to normal thyroid tissues, suggesting a possible role of the chaperones in carcinogenesis, probably related to its role in maintaining the homeostasis of the proteins involved in mitochondrial bioenergetics and redox balance [23,24].