Molecular Analysis of Thyroid Cancer Without ^Sup 131^I Uptake

By Anonymous

Mian et al. from the University of Padua (Italy) reported on September 14 ahead of print in Clinical Endocrinology (Oxford) on a histologic study of the molecular characteristics associated with a subset of papillary thyroid cancers (PTCs) with no ^sup 131^I uptake. The study included 48 PTC tissues divided into 3 groups: (1) 28 primary cancers; (2) 7 recurrences capable of trapping ^sup 131^I; and (3) 13 recurrences incapable of trapping ^sup 131^I. mRNA levels of sodium/ iodide symporter (NIS), thyroglobulin, and thyroperoxidase and pendrin genes, glycolytic metabolism genes, and BRAF mutations were assessed and compared among the groups. Tissues with no ^sup 131^I uptake had slightly reduced NIS; significantly reduced thyroglobulin, thyroperoxidase, and pendrin; and significantly increased GLUT-1 gene expression levels and a high frequency of BRAF mutations (77%). A BRAF (V600E) mutation in both primary and metastatic thyroid cancers was associated with a marked drop in thyroperoxidase and pendrin expression and a considerable increase in GLUT-1 expression. The authors concluded that the loss of ^sup 131^I uptake in recurrences depends not only on a decrease in NIS gene activity but possibly on a reduction in the molecules regulating its intracellular metabolism, that the high GLUT-1 gene expression supports the use of PET with specific tracers in the clinical management of such cancers, and that BRAF (V600E) point mutations may lead to less differentiated phenotypes, suggesting worse prognoses. Clinical Endocrinology (Oxford)

Copyright Society of Nuclear Medicine Nov 2007

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