We examined the expression levels of transcription factors involved in thyroid development [thyroid transcription factor 1 (TTF-1), paired box gene 8 (PAX-8) and haematopoietically expressed homeobox (HEX)] in 101 thyroid tissues, including 14 normal thyroid tissues, 13 hyperfunctioning tissues, 27 benign adenomas and 47 follicular or papillary carcinomas.
TSHR, TTF-1 and TRbeta1 levels were significantly lower in oncocytic tumours than in papillary carcinomas, as a result of specific biological changes in oncocytic tumours.