Investigation of Calcitonin and Calcitonin Gene-related Peptide in 88 Cases of Medullary Thyroid Carcinoma

Abstract

Objective: To investigate the changes of calcitonin (CT) and calcitonin gene-related peptide (CGRP) in patients with medullary thyroid carcinoma (MTC). Methods: Fifty-eight cases of MTC were selected and the relationship between the CT levels and metastasis was investigated. The immunohistochemical method was used to detect the expression of CT and CGRP in the 58 samples of MTC tissues. The CT and CGRP in 30 newly diagnosed MTC inpatients were measured before operation and in the first few days after operation using a radioimmunoassy. Results: (1) The rate of residual tumor had a significant difference between the normal serum CT group one month after operation and the elevated group at the same period (P <0.01).(2) Immunohistochemical study revealed the positive rate of CT was about 98%, and that of the CGRP was 87.8%. (3) Part of the patients had an elevated CGRP levels while CT levels was normal. (4) The serum CT levels were decreased to a stable range one week after operation. Conclusion: CT is a useful index to evaluate the efficacy of surgical treatment. The measurement of serum CGRP is helpful in the diagnosis of MTC, especially for those whose preoperative CT levels are normal.Medullary thyroid carcinoma (MTC) is a malignant tumor of the parafollicular cells of the thyroid and has a poorer prognosis in thyroid cancer. Calcitonin (CT) secreted by thyroid parafollicular cells remains the cornerstone of clinical management as a serum tumor marker for MTC, but the nature of the changes of CT after operation is not clear. Also in some patients with MTC, they have a normal preoperative CT level. Calcitonin gene-related peptide (CGRP) is an alternate product of the CT gene, so it is a possible tumor marker for MTC [1,2] .In this study, in order to offer a basis for the diagnosis, treatment and prognosis for MTC patients, an immunohistochemical investigation for CT and CGRP was performed on tumor tissues from 58 patients with MTC. A radioimmunoassy was used to investigate the pattern of changes of CT and CGRP before and after operation.