EXPERIMENTAL STUDY Evaluation of insulin-like growth factor II, cyclooxygenase-2, ets-1 and thyroid-specific thyroglobulin mRNA expression in benign and malignant thyroid tumours D Fuhrer, M Eszlinger, S Karger, K Krause, C Engelhardt, D Hasenclever 1 , H Dralle 2 and R Paschke III Medical Department, Universityof Leipzig, Ph-Rosenthal-Str. 27, 04103 Leipzig, Germany, 1 Department of Statistics, University of Leipzig, Leipzig, Germany and 2 Department of Surgery, Martin-Luther University Halle, Halle, Germany (Correspondence should be addressed to D Fuhrer; Email: fued@medizin.uni-leipzig.de) Abstract Objective: We evaluated three markers (insulin-like growth factor II (IGF-II), cyclooxygenase-2 (COX-2) and ets-1) of thyroid growth stimulation and cell transformation together with a thyroid- specific marker (thyroglobulin (Tg)) for their potential to differentiate benign and malignant follicular thyroid neoplasia (FN). Design and methods: mRNA expression levels were determined by real-time PCR in 100 snap-frozen thyroid samples: 36 benign thyroid nodules with different histology and function (19 cold (CTN) and 17 toxic thyroid nodules (TTN)), 36 corresponding normal thyroid tissues of the same patients, eight Graves’ disease (GD) thyroids, 10 follicular thyroid carcinomas (FTC) and 10 papillary thyroid carcinomas (PTC). Results: Mean IGF-II and COX-2 levels were not significantly altered between benign and malignant thyroid nodules (IGF-II) or nodular (FTC, TTN, CTN) and normal thyroid tissues (COX-2). In contrast, eight- to tenfold upregulation of ets-1 was observed in PTC and three- to fourfold upregulation of ets-1 was observed in FTC (and GD) compared with benign thyroid nodules and normal thyroid tissues. In addition, thyroglobulin mRNA expression was markedly downregulated (50- to 100-fold) in FTC, PTC and GD samples compared with benign nodular and normal thyroid tissues. Hence an ets-1/Tg ratio . 20 distinguished differentiated thyroid cancer from benign nodular or normal thyroid tissue. We then studied ets1- and Tg mRNA expression levels in fine needle aspiration cytology (FNAC) samples. However, in a consecutive series of 40 FNAC samples only equivocal results were obtained on 38 benign and two malignant (FTC) thyroid tumour samples. Conclusions: Upregulation of ets-1 and downregulation of Tg mRNA expression occur in differentiated thyroid cancer and may facilitate pre-operative identification of thyroid malignancy depending on further evaluation of these potentially promising markers in a larger series of benign and malignant thyroid tumours and their FNAC samples. European Journal of Endocrinology 152 785–790 Introduction Fine needle aspiration cytology (FNAC) is the most sensitive and specific tool for pre-operative diagnosis of thyroid malignancy (1–4). However, there are sev- eral shortcomings to FNAC, such as sample quality and analysis as well as diagnostic limitations, in par- ticular follicular thyroid neoplasia (FN) (4, 5). As a consequence, patients with nodular thyroid disease will possibly undergo thyroid surgery too frequently, because of the lack of tools to confidently assure the patient about the ‘benignity’ of the disease. This is most apparent in areas with iodide deficiency, where the clinician is faced with the dilemma to identify very rare thyroid cancer amongst very frequent thyroid nodular disease (1–3). The search for mutations in ‘candidate’ genes, e.g. ras, has not been fruitful and PAX-8/PPARg rearrangements seem to be too infrequent in follicular thyroid cancer (FTC) (, 35%) to allow for a routine appli- cation as a diagnostic marker of FN (6–8). Other markers, in particular galectin-3, have been reported to delineate benign and malignant FN with high sen- sitivity and specificity; however, more recent studies suggest that galectin-3 is useful for the diagnosis of papillary thyroid cancer and less so for FTC (9, 10). In view of the considerable heterogeneity of benign thyroid nodules (3, 5), it is conceivable that a combi- nation of parameters rather than one single diagnos- tic parameter needs to be applied. European Journal of Endocrinology (2005) 152 785–790 ISSN 0804-4643 q 2005 Society of the European Journal of Endocrinology DOI: 10.1530/eje.1.01912 Online version via www.eje-online.org