Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

UNLABELLED: The follow-up of differentiated thyroid cancer (DTC) is currently performed by serum Tg levels determination and whole body scan (WBS) with 131I. In this regard, the latter represents the main tool to localize metastatic tissue, but is characterized by the induction of severe hypothyroidism. Moreover, WBS displays poor sensitivity in poorly differentiated tumors due to a loss of iodine uptake capacity. AIM: In this study we describe an alternative tracer, radiolabeled rhTSH, for the diagnosis of non-iodine uptaking DTC metastases. METHODS: rhTSH was iodinated with 125I or 123I using an enzymatic method with lactoperoxidase/glucose oxidase. In vitro stability of labeled compounds was assessed in saline and serum and in vivo studies were performed in tumor-bearing nude mice. Three mice were inoculated with ARO cells (TSH receptor negative) and three with PTC-1 cells (TSH receptor positive). After 25 days, mice were injected with 10 microg of 123I-rhTSH (100 microCi) and static images were acquired at 30 minutes, 1, 2, and 3 hours. Animals were then sacrificed and dissected for organ counting. RESULTS: RhTSH was radioiodinated to high specific activity: 132.2 mCi/mg for 123I-rhTSH, 94.3 for 125I-rhTSH. In vitro stability tests revealed no significant release of radioiodine. A clear tumor uptake was detectable after 2 hours in all animals implanted with PTC-1. CONCLUSION: Results obtained so far suggest that radiolabeled rhTSH might be a promising radiopharmaceutical for diagnosis and follow-up of DTC.

Original publication

DOI

10.1089/108497804773391685

Type

Journal article

Journal

Cancer Biother Radiopharm

Publication Date

02/2004

Volume

19

Pages

57 - 63

Keywords

Animals, Cell Line, Tumor, Humans, Iodine Radioisotopes, Mice, Mice, Nude, Neoplasm Metastasis, Quality Control, Radiopharmaceuticals, Recombinant Proteins, Thyroid Neoplasms, Thyrotropin, Tissue Distribution, Xenograft Model Antitumor Assays