In the German Association of Endocrine Surgeons practice guidelines for the surgical management of malignant thyroid tumors [43], total thyroidectomy is generally warranted if stimulated calcitonin serum levels are higher than 100 pg/mL in adults since the risk of MTC is considered to be substantial if this cut-off value is exceeded. The gene discussed is CALCA; the disease is medullary thyroid gland carcinoma.