Calcitonin:Mean CT level was 14.53 ± 6.13 (10–43 pg/mL) in benign nodular goiter group, 39.93 ± 28.53 (10–85 pg/mL) in the MTC group, 14.57 ± 3.3 pg/mL (11-18 pg/mL) in CHH and 15.79 ± 4.14 pg/mL (10–23 pg/mL) in nonMTC thyroid cancer group. The gene discussed is CALCA; the disease is medullary thyroid gland carcinoma.