Measurement of Calcitonin and Calcitonin Gene-Related Peptide mRNA Refines the Management of Patients with Medullary Thyroid Cancer and May Replace Calcitonin-Stimulation Tests

Author(s):Show less -

Camacho, Cleber P. ^[1] ; Lindsey, Susan C. ^[1] ; Melo, Maria Clara C. ^[1] ; Yang, Ji H. ^[1] ; Germano-Neto, Fausto ^[1] ; Valente, Flavia de O. F. ^[1] ; Lima, Thiago R. N. ^[2] ; Biscolla, Rosa Paula M. ^[1] ; Vieira, Jose G. H. ^[1] ; Cerutti, Janete M. ^[2] ; Dias-da-Silva, Magnus R. ^[1] ; Maciel, Rui M. B. ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Escola Paulista Med, Dept Med, Lab Mol & Translat Endocrinol, BR-04039032 Sao Paulo - Brazil

^[2] Univ Fed Sao Paulo, Escola Paulista Med, Dept Genet, BR-04039032 Sao Paulo - Brazil

• Document type: Journal article
• Source: THYROID; v. 23, n. 3, p. 308-316, MAR 2013.
• Web of Science Citations: 12

Abstract

Background: Serum calcitonin (sCT) is the main tumor marker for medullary thyroid cancer (MTC), but it has certain limitations. Various sCT assays may have important intra-assay or interassay variation and may yield different and sometimes conflicting results. A pentagastrin-or calcium-stimulation calcitonin (CT) test may be desirable in some situations. Alternatively, or in the absence of the stimulation test, mRNA detection offers the advantages of being more comfortable and less invasive; it only requires blood collection and has no side effects. The objective of this study was to investigate the applicability of measuring calcitonin-related polypeptide alpha (CALCA) gene transcripts (CT-CALCA and calcitonin gene-related peptide {[}CGRP]-CALCA) in patients with MTC and in relatives diagnosed with a RET mutation and to test mRNA as an alternative diagnostic tool for the calcitonin-stimulation test. Methods: Twenty-three healthy controls and 26 individuals evaluated for MTC were selected, including patients with sporadic or hereditary MTC and RET mutation-carrying relatives. For molecular analysis, RNA was extracted from peripheral blood, followed by cDNA synthesis using 3.5 mu g of total RNA. Quantitative real-time polymerase chain reaction (RT-qPCR) was performed with SYBR Green and 200nM of each primer for the two specific mRNA targets (CT-CALCA or CGRP-CALCA) and normalized with the ribosomal protein S8 as the reference gene. Results: We detected CALCA transcripts in the blood samples and observed a positive correlation between them (r = 0.946, p < 0.0001). Both mRNAs also correlated with sCT (CT-CALCA, r = 0.713, p < 0.0001; CGRP-CALCA, r = 0.714, p < 0.0001). The relative expression of CT-CALCA and CGRP-CALCA presented higher clinical sensitivity (86.67 and 100, respectively), specificity (97.06 and 97.06), positive predictive value (92.86 and 93.75), and negative predictive value (94.29 and 100), than did sCT (73.33, 82.35, 64.71, and 87.50, respectively). In addition, the CALCA transcript measurement mirrored the response to the pentagastrin test. Conclusion: We demonstrate that the measurement of CALCA gene transcripts in the bloodstream is feasible and may refine the management of patients with MTC and RET mutation-carrying relatives. We propose considering the application of this diagnostic tool as an alternative to the calcitonin-stimulation test. (AU)

• FAPESP's process: 11/20747-8 - Clinical, biochemical and molecular investigation of Thyrotoxic periodic paralysis
• Grantee: Magnus Régios Dias da Silva
• Support Opportunities: Regular Research Grants
• FAPESP's process: 06/60402-1 - Medular carcinoma of the thyroid: revisiting the clinical, molecular biological, biochemical and biological aspects following findings of molecular genetics
• Grantee: Rui Monteiro de Barros Maciel
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 09/11257-7 - Functional Role of Arginase II (ARG2) in the Pathogenesis of Thyroid Tumors
• Grantee: Janete Maria Cerutti
• Support Opportunities: Regular Research Grants