High sensitivity of pretargeted immunoscintigraphy using murine or chimeric anti-CEA BsMAb and pretargeted haptens-peptides labeled with <sup>111</sup>In or <sup>131</sup>I were reported in metastatic MTC patients 20 years ago.
CEA = carcinoembryonic antigen CT = computed tomography <sup>18</sup>F-FDG = <sup>18</sup>F-fluorodeoxyglucose MTC = medullary thyroid cancer PET = positron emission tomography PVE = proportion of variance explained sCT = serum calcitonin SUV = standard uptake value US = ultrasound.
FoxA1 discriminates between medullary thyroid carcinoma and tumors of follicular derivation with sensitivity and specificity greater than calcitonin and CEA; therefore, it may serve as a reliable ancillary marker for the diagnosis of medullary thyroid carcinoma because of its reliably uniform quality of staining.
These results demonstrate that, in addition to the expression of RET, calcitonin and CEA, PGP9.5 mRNA expression may contribute to the molecular-based diagnosis of MTCs.