Mortalin depletion induces not only cell cycle arrest by altering MEK/ERK signaling but also induces caspase-dependent apoptotic cell death, Figure 2B. These data suggest that mortalin could be a target for treatment, since it is a key regulator of cell signaling and metabolism in MTC [23,32]. Here, HSPA9 is linked to medullary thyroid gland carcinoma.