Medullary thyroid cancer was predicted in 100% of the male patients with bCT concentrations > 43 pg/mL (sensitivity: 58%) or Pg-sCT > 470 pg/mL (sensitivity: 67%) and Ca-sCT > 1500 pg/mL (sensitivity: 54%) and in 100% of the female subjects with bCT concentrations > 23 pg/mL (sensitivity: 80%) or Pg-sCT concentrations > 200 pg/mL (sensitivity: 80%) and Ca-sCT concentrations > 780 pg/mL (sensitivity: 67%), respectively. This evidence concerns the gene JUP and medullary thyroid gland carcinoma.