EXPRESSION OF THE CALCITONIN-GENE FAMILY IN MEDULLARY-THYROID CARCINOMA

The regulatory peptide calcitonin was discovered in 1962. During the l ast decade it has been demonstrated to be part of a gene family. Calci tonin is synthesized in the parafollicular cells (C cells) of the thyr oid gland. These cells give rise to an endocrine tumor, medullary thyr oid carcinoma (MTC), which is found in a sporadic and an inherited for m. Calcitonin is used as a tumor marker for MTC. The calcitonin gene w as demonstrated in 1981 to give rise to an alternative peptide product , alpha-CGRP, and a second gene encoding a very similar peptide, beta- CGRP, has also been identified. A third CGRP-like peptide, amylin, was identified in 1986. This article summarizes the present knowledge abo ut gene structure, regulation of gene expression, and expression of th e calcitonin gene family in MTC and in MTC-derived cell lines. The met hods employed for detection of gene expression and for measurement and characterization of peptide products are described, and finally the r elevance of biochemical tumor markers is discussed in relation to the new diagnostic methods for inherited MTC based on molecular biological techniques. (C) 1997 Elsevier Science Inc.