Type I 5 '-iodothyronine deiodinase activity and mRNA are remarkably reduced in renal clear cell carcinoma

The purpose of this study was to compare thyroid hormone metabolism between non-cancerous tumor-surrounding human kidney tissues and renal clear cell carcinomas (RCCC). The material consisted of samples taken from 10 RCCC pat ients of both sexes and three grades of differentiation, GZ to G3. We showe d that, similar to rat tissue, type I 5 ' monodeiodinase (5 ' DI) expressio n is heterogeneous within the human kidney. We also found a poor correlatio n between 5 ' DI activity and mRNA level in non-cancerous tumor-surrounding tissue suggesting significant post-transcriptional regulation of 5 ' DI ex pression by an unidentified process in the human kidney, in all RCCC tissue s both 5 ' DI activity and mRNA levels were undetectable. This suggests eit her loss of human 5 ' DI gene expression during neoplastic transformation o r the origination of RCCC from a tubular cell type that does not express 5 ' DI. (C) 2001, Editrice Kurtis.