Medullary thyroid carcinomas in cell culture--models for future therapies.

We report the successful establishment of seven human medullary thyroid carcinomas (MTC) as continuous cell lines. Characteristic features--such as the presence of neuroendocrine granules--and the positive immunoreactivity to antibodies to CT, CGRP, GRP, SRIF, 5-HT, NSE, PHE, LK2H10, ER and Pgr were followed throughout the cultivation. An overexpression of the antiapoptotic gene bcl-2 was detected in the cell lines. Deregulation of apoptosis plays an important role in multistep tumorigenesis. MTCs are known for the phenomenon of bcl-2-based chemo- and radioresistance. Our studies focus on influencing the growth rates and modulating the apoptotic rates by treatment with proliferation-modifying substances and anticancer drugs. Our MTC cell lines are useful models for these in vitro studies.