Quantitative measurement of thyroglobulin mRNA in peripheral blood of patients after total thyroidectomy

Previous studies have reported the clinical usefulness of reverse transcrip tion-polymerase chain reaction (RT-PCR) detection of thyroglobulin (TG) mRN A in the peripheral blood of patients with differentiated thyroid carcinoma . To evaluate this usefulness, we measured TG mRNA in the peripheral blood of patients diagnosed with thyroid carcinoma after total thyroidectomy by r eal-time quantitative RT-PCR using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA as an internal control. Surprisingly, we detected TG mRNA in all samples obtained after total thyroidectomy, including those from 4 medu llary carcinomas. Further. there was no statistical difference in expressio n levels of TG mRNA in the patients with or without metastasis, and no sign ificant correlation was found between serum TG concentrations and the expre ssion levels of TG mRNA. These results give rise to a question regarding th e clinical applications of not only RT-PCR detection but also quantitative measurement of TG mRNA in peripheral blood. (C) 2001 Cancer Research Campai gn http://www.bjcancer.com.