Technology insight: gene therapy and its potential role in the treatment of medullary thyroid carcinoma.

Metastatic medullary thyroid cancer (MTC) responds poorly to conventional treatments with chemotherapy and radiotherapy. Gene therapy--the transfer of genetic material for therapeutic purposes--might have therapeutic potential for patients with progressive metastatic MTC that is incurable by conventional treatments. To date, a number of gene-therapy strategies have been explored, primarily those that use replication-deficient adenovirus vectors to transfer therapeutic genes to tumor cells. Tissue-specific expression of the promoter for calcitonin and calcitonin-related polypeptide alpha has allowed therapeutic genes to be specifically expressed in calcitonin-secreting cells and in the MTC tumors derived from them; such tissue-specific expression contributes to improved safety of gene therapies and has the potential to increase their therapeutic index. In addition, the identification of an MTC-specific peptide ligand raises the possibility of developing an MTC-selective vector. In this article, we have described the exciting area of gene therapy in the management of MTC with a focus on preclinical in vitro and in vivo MTC models.