Sodium iodide symporter expression and radioiodine distribution in extrathyroidal tissues

Abstract

The functional role of the sodium iodide symporter (NIS) in extrathyroidal tissues was investigated by examining its mRNA and protein expression, together with the evidence of radioiodine (131)I uptake in 302 patients who underwent (131)I total body scanning, following the administration of high doses of (131)I for a papillary or follicular thyroid carcinoma. By using a real-time kinetic quantitative RT-PCR and immunohistochemistry, the expression of NIS protein was detected mainly in secretory tissues. In parallel, 1311 uptake was evidenced in the majority of patients in the salivary glands (in 39%) and stomach (in 78%), but was found in breast in only 4 young female patients. These data demonstrate a strong correlation between the organ radioactivity distribution, as observed in vivo, and NIS protein expression. Interestingly, (131)I is rarely concentrated by mammary glands, even when large doses are administered. Moreover, a (131)I transfer in secretion fluids may represent a potential source of contamination responsible for false positive images and diagnostic pitfalls.

Expression of sodium-iodide symporter mRNA in the thyroid gland of Xenopus laevis tadpoles: developmental expression, effects of antithyroidal compounds, and regulation by TSH

“…The physiological meaning of NIS expression in stomach and kidney of X. laevis is not yet clear. The tissue distribution of NIS mRNA observed in X. laevis tadpoles is in accordance with several mammalian studies reporting increased NIS expression in thyroid and gastric mucosa but very low or undetectable levels in liver, heart, and lung (Perron et al 2001, Bruno et al 2004. Inconsistent results have been obtained in mammalian studies of NIS expression in the kidney.…”

“…Inconsistent results have been obtained in mammalian studies of NIS expression in the kidney. Spitzweg et al (2001) reported positive detection of NIS mRNA in human kidney by RT-PCR and ribonuclease protection assay, whereas other studies failed to detect NIS in kidney using various techniques (Perron et al 2001, Bruno et al 2004. During spontaneous development, the level of NIS mRNA expression in thyroid glands of X. laevis tadpoles showed distinct changes.…”

Risk of Breast Cancer in Patients with Thyroid Cancer Receiving or Not Receiving 131I Treatment: A Nationwide Population-Based Cohort Study

“…The NIS is also found in the breasts, salivary lacrimal glands, gastric mucosa, and ovaries (14,15). However, concerns have been raised regarding radioactive iodine therapy, because of the potential for the development of second primary malignancy, including breast cancer (16).…”

Hyperprolactinemia-Associated Breast Uptake of Radioiodine Following 131I Postablation Scan in Differentiated Thyroid Cancer

“…These observations are based on animal models or cell lines [5,11], but never confirmed in humans in vivo. Hyperprolactinemia associated uptake of radioiodine into breast was reported in other cases, suggesting a cause and effect relationship between a high level of endogenous prolactin and breast radioiodine uptake [3,4,12]. In a previous study, of 302 patients who had thyroid cancer and who underwent 131 I whole body scans, breast uptake was observed in 4 cases.…”

“…In a previous study, of 302 patients who had thyroid cancer and who underwent 131 I whole body scans, breast uptake was observed in 4 cases. One of them had been treated with the anti-dopaminergic drug, sulpiride [12]. The prevalence of drug-induced hyperprolactinemia is underestimated due to the frequent lack of externally visible symptoms, and the reluctance to report it due to the embarrassing nature of the symptoms.…”