TSH receptor status of thyroid neoplasms - TaqMan RT-PCR analysis of archival material

Regulation of thyroid follicular cell proliferation and function is mediate d by the interaction of TSH with its receptor (TSHr) on the plasma membrane . While it is recognized clinically that responsiveness of thyroid epitheli al tumours to TSH varies with the histological type and grade of neoplasm, the level of TSHr expression in these different tumours has not been quanti fied hitherto. The aim of this study was to provide this information. Total RNA was extracted from 125 samples of formalin-fixed, paraffin-embedded th yroid tissue comprising 48 papillary (PTC), 29 follicular (FTC), eight anap lastic (ATC), and five medullary thyroid carcinomas (MTC), in addition to 3 5 samples of either follicular adenoma CFA) or normal thyroid tissue. Sampl es were reverse-transcribed and analysed using TaqMan polymerase chain reac tion (PCR). TSHr expression was shown to be similar to normal in FA and inv ersely related to the grade of the majority of thyroid cancers other than M TC, in which, as expected, there was negligible expression. It is concluded that reduced expression of TSHr implies decreased responsiveness to TSH ma nipulation and is therefore a clinically important prognostic indicator in thyroid cancers. Copyright (C) 1999 John Wiley & Sons, Ltd.