Immunohistochemical study of the medullary thyroid carcinoma with reference to C-thyroglobulin reaction of tumor cells

Twelve cases of medullary thyroid carcinoma were investigated ty the immunoperoxidase method using anti-calcitonin, anti-C-thyroglobulin (C-Tg, C cell-immunoreactive thyroglobulin) and anti-19S thyroglobulin antisera. Tumor cells as well as normal C cells revealed distinct immunoreaction for C-Tg besides for calcitonin. In contrast to normal C cells, the tumor cells were stained more intensely by anti-Ctg antiserum than by anti-calcitonin antiserum. Furthermore, there occurred several tumors or some areas of tumors which showed strong response to anti-C-Tg antiserum but weak or no response to anti-calcitonin antiserum. Thus, medullary carcinoma cells synthesized far greater amounts of C-Tg than calcitonin. The small follicles were occasionally observed mingled in typical cell solid masses. They stored colloid-like materials which were intensely immunoreactive to C-Tg but nonreactive to calcitonin. The specific immunoreaction patterns to anti-C-Tg and anti-calcitonin antisera were also obtained on the ground materials of the amyloid. On the histogenesis of amyloids of medullary carcinoma, the C-Tg could be the presursor of the fibrillar protein of amyloids and the component of the fibrillar protein also closely related to calcitonin.