The tumors were consistent with a neuroendocrine phenotype; showing strong immunoreactivity to chromogranin A and synaptophysin, but the immunohistochemical profile was inconsistent with medullary thyroid carcinoma in that the tumor was negative for calcitonin, CEA and TTF-1 (Figure 2). This evidence concerns the gene CEACAM5 and medullary thyroid gland carcinoma.