This Article Abstract Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tonacchera, M. Articles by Vitti, P. Search for Related Content PubMed PubMed Citation Articles by Tonacchera, M. Articles by Vitti, P. Pubmed/NCBI databases Substance via MeSH Medline Plus Health Information Thyroid Cancer

Benign Nonfunctioning Thyroid Adenomas Are Characterized by a Defective Targeting to Cell Membrane or a Reduced Expression of the Sodium Iodide Symporter Protein

Dipartimento di Endocrinologia e Metabolismo (M.T., P.A., G.D.M., A.Pe., C.D.C., M.D.S., F.L., A.Pi., L.C., P.Vit.), Ortopedia e Traumatologia, Medicina del Lavoro; Dipartimento di Oncologia (P.Via., A.G.N.), Sezione Anatomia Patologica; and Dipartimento di Clinica Chirurgica (P.M.), Università di Pisa, 56124 Pisa, Italy

Address all correspondence and requests for reprints to: Massimo Tonacchera, Dipartimento di Endocrinologia, Università degli Studi di Pisa, Via Paradisa 2, 56124, Cisanello, Pisa, Italy.

	Abstract

Top Abstract Introduction Patients and Methods Results Discussion References

 
Nodular thyroid disease is the most common endocrine disorder. Nonfunctioning thyroid nodules are identified by their low radioiodide uptake compared with the normal extranodular tissue, which, at thyroid scintiscan, produces the typical picture of a cold thyroid nodule. Previous in vitro studies demonstrated that the majority of nonfunctioning thyroid nodules have a specific defect in iodide transport that accounts for their failure to accumulate radioactive iodide in vivo. A defect in the expression or structure of the sodium iodide symporter (NIS) gene has been hypothesized as a possible cause of the impaired iodide trapping in nonfunctioning thyroid nodules.

We studied 22 patients who were submitted to surgery for a solitary nonfunctioning thyroid nodule that originated in an otherwise normal gland. Thyroid scintigraphy was performed at 1, 2, 3, 4, 6, and 24 h after the oral administration of a tracer dose of ¹³¹I (iodine). All patients showed absence of ¹³¹I uptake in the nodule, with normal uptake in the extranodular tissue and in the contralateral thyroid lobe. Eight patients with toxic adenomas who underwent lobectomy were also included in the study. We first studied the expression of human NIS (hNIS) protein by immunohistochemistry in paraffin-embedded tissue sections using a specific anti-hNIS monoclonal antibody. Subsequently, we searched for somatic mutations of hNIS gene in nonfunctioning thyroid nodules.

The level of hNIS expression was determined in both the nodules and the normal tissue from the same thyroid gland. In all functioning thyroid nodules (toxic adenomas), a high expression of hNIS protein was detected with respect to normal surrounding tissue. Similar to the normal thyroid tissue, follicular cells of toxic thyroid adenomas showed an exclusive expression of hNIS protein at the cell membrane. Fifty-four percent of benign nonfunctioning thyroid nodules overexpressed hNIS protein compared with the normal surrounding tissue, but in these nodules the hNIS protein failed to target the cell membrane, being mostly localized inside the cytoplasm. hNIS protein was not detected by immunohistochemistry in 46% of nonfunctioning nodules, whereas it was expressed in the surrounding unaffected thyroid tissue. Direct sequencing of the hNIS gene in all of the nonfunctioning nodules did not reveal major genetic alterations. A silent polymorphism (GCC/GCG codon 544, exon 13) was found in one nodule.

In conclusion, the results obtained in this study show that two mechanisms contribute to the reduced radioiodide uptake typical of benign nonfunctioning thyroid nodules: 1) reduced expression of the hNIS protein, and 2) defective targeting of hNIS to the cell membrane.

	Introduction

Top Abstract Introduction Patients and Methods Results Discussion References

 
THYROID NODULES ARE the most common endocrine disorder (1, 2, 3). Thyroid nodules can be detected in an otherwise normal gland (1, 2), but especially in iodine-deficient areas multiple nodules are often present in an enlarged thyroid gland (multinodular goiter) (1, 2). At scintigraphy, thyroid nodules can be subdivided into functioning and nonfunctioning (1, 2, 3). Nonfunctioning nodules are those that, compared with the normal thyroid tissue, take up little or no radioiodine. This peculiarity confers to nonfunctioning nodules the typical cold appearance at thyroid scintiscan. Previous in vitro studies demonstrated that the majority of nonfunctioning thyroid nodules have a specific defect in iodide transport that accounts for their failure to accumulate radioactive iodide (4). In some nonfunctioning nodules, the iodide trapping step is conserved while the mechanism of iodide organification is defective (5). In the latter case the nodule, depending on the time when the thyroid scintiscan is performed, will appear as functioning at 1 h and nonfunctioning (cold) at 24 h after the administration of a tracer dose of ¹³¹I. This is because radioactive iodine is rapidly lost from thyroid cells if the organification process is defective (5).

A defect in the expression or the structure of the sodium iodide symporter (NIS) can be hypothesized in thyroid nodules showing an impaired iodide trapping. Recently, the NIS from the rat was cloned and sequenced (6), leading also to the sequencing of the human NIS (hNIS) (7). NIS is a membrane-bound glycoprotein located at the basolateral portion of the thyroid follicular cell (8). NIS concentrates iodide in thyroid cells by an active transport process that, counteracting an electrochemical gradient, maintains iodide concentration inside thyroid cells about 20- to 100-fold higher than in serum. The hNIS is predicted to have a serpentine structure of probably 13 transmembrane segments with extracellular N and intracellular C termini (8). hNIS gene is located on chromosome 19. It consists of 15 exons and encodes a protein of 643 amino acids (7). The expression of hNIS has been investigated in benign and malignant thyroid nodules by RT-PCR, real-time PCR, and immunohistochemistry. Until recently hNIS expression was found to be low in all benign and malignant thyroid nodules by both methods (9, 10, 11, 12). However, a few months ago, Dohan et al. (13) showed by immunohistochemistry that 70% of malignant nonfunctioning thyroid nodules had an overexpression of hNIS protein that was predominantly confined to the cytoplasm (13).

In this paper, we studied hNIS protein expression by immunohistochemistry in 22 isolated nonfunctioning nodules from patients who underwent lobectomy. Before surgery, all patients were investigated with thyroid scintigraphy performed at 1, 2, 3, 4, 6, and 24 h after an oral tracer dose of ¹³¹I. All nodules included in the study were unable to trap iodide at any time after ¹³¹I administration, suggesting a defect in the machinery of intracellular iodide concentration. The level of expression of hNIS protein was determined both in the nodules and in the normal tissue from the same thyroid glands. In all of the nodules we also searched for somatic hNIS gene mutations. Our results show that 54% of benign nonfunctioning thyroid nodules overexpressed hNIS with respect to the normal surrounding tissue. However, hNIS protein was mostly localized in the cytoplasm and failed to reach the plasma membrane. In 46% of nonfunctioning nodules, the expression of hNIS was absent in the nodular tissue while present in the surrounding normal tissue. In all of the nonfunctioning nodules, the genetic analysis did not reveal any mutation in the coding region of the hNIS gene.

	Patients and Methods

Top Abstract Introduction Patients and Methods Results Discussion References

 
Patients, thyroid uptake, and scintigraphy

Twenty-two patients submitted to surgery for a solitary nonfunctioning thyroid nodule that originated in an otherwise normal gland were included in this study. Thyroid uptake was performed at 1, 2, 3, 4, 6, and 24 h after the oral administration of a tracer dose of ¹³¹I (50 µCi, 1.85 MBq) measuring the radioactive activity on the neck and the background for 1 min (Atomlab, Biodex Medical System, Shirley, NY). At the same time, thyroid scintigraphy was performed using a -camera (Apex SPX-one head, Elscint, Milan, Italy).

All patients showed absence of ¹³¹I uptake in the nodule with normal uptake in the extranodular tissue and in the contralateral thyroid lobe. Cytological smears by fine-needle aspiration showed a pattern of follicular adenoma in all nodules. All patients were euthyroid. Thyroid autoimmunity was excluded for the absence of circulating Tg, thyroperoxidase, and TSH-receptor antibodies. Thyroid lobectomy was performed in all patients.

Eight patients who underwent lobectomy for a toxic thyroid adenoma were also included in the study. All of the patients showed an exclusive accumulation of ¹³¹I in the nodule, with functional suppression of the remaining parenchyma at thyroid scintiscan. All of these patients were hyperthyroid (with elevated FT4 and FT3 serum concentrations and undetectable serum TSH levels).

In vitro tests

FT4 and FT3 were measured by a RIA after chromatographic separation of the free hormone (FT4 RIA, FT3 RIA, Lysophase, Technogenetics S.r.l., Milan, Italy). TSH was assessed by a sensitive assay (AutoDELFIA hTSH Kit, Pharmacia s.p.a., Milan, Italy). Thyroperoxidase and Tg antibodies were measured by passive agglutination (SERODIA-AMC and SERODIA-ATG, Fujirebio, Tokyo, Japan). We searched for TSH-receptor antibodies using a commercial RRA (TRAK assay, BRAHMS, Berlin, Germany).

Immunohistochemistry

Tissues were fixed in 10% formalin and embedded in paraffin. Sections (5 µm) were stained with hematoxylin-eosin for histological evaluation. Five additional 5-µm sections were used for immunohistochemistry. The sections were incubated with a monoclonal antibody recognizing hNIS (dilution 1:30). This antibody was obtained by genetic immunization (a kind gift from Dr. S. Costagliola, Institut de Recherche Interdisciplinaire en Biologie Humaine et Nucléaire, Brussels, Belgium) as described by Pohlenz et al. (14).

The 5-µm sections were deparaffinized in xylene and rehydrated in alcohol. Endogenous peroxide activity was blocked by incubating the slides in 1% hydrogen peroxide in methanol for 10 min. To unmask the antigens, the slides were microwave-treated in 10 mM citrate buffer (pH 6) for a total of 10 min. After nonspecific staining was blocked with normal serum, the sections were incubated with the primary antibody. Then, the sections were incubated with biotin-labeled secondary antibody (dilution 1:500) and avidin-biotin-complex (Vector Laboratories, Inc., Burlingame, CA) for 30 min, respectively. 3–3'-Diaminobenzidine tetrahydrochloride was used as chromogen. Finally, the sections were counterstained with hematoxylin, dehydrated, and mounted. Immunohistochemistry for hNIS protein expression was performed in both the nodular tissue and the surrounding healthy tissue in all samples. Negative controls were obtained by omitting the primary antibodies. Evaluation parameters were as follows: 1) percentage of follicular cells showing a positive staining for hNIS, 1–10% (+), 11–29% (2+), and more than 30% (2++); and 2) site of hNIS cell positivity was cell membrane or cytoplasm.

Genomic DNA extraction, PCR of exons of NIS DNA, and direct sequencing

Genomic DNA was extracted from all nonfunctioning thyroid nodules and from normal extranodular tissue as previously described (15). Each exon of the hNIS gene was PCR-amplified using a pair of primers derived from the flanking introns. Exons 2 and 3, 6 and 7, 9 and 10, 11 and 12 were coamplified with an intervening intron. Nucleotide sequences of all exons and all exon-intron boundaries containing at least 15 nucleotides in introns were determined in both orientations by direct sequencing using AmpliTaqDNA polymerase FS, with an ABI Prism Bigdye terminator cycle sequencing kit (ABI 373 PE, PE Applied Biosystems, Foster City, CA) following the protocol of the supplier. Sequencing products were analyzed on a model 373 A sequencer (PE Applied Biosystems). The primers used are listed in Table 1.

	Results

Top Abstract Introduction Patients and Methods Results Discussion References

Histology. All functioning nodules showed the typical aspect of thyroid adenomas. They were surrounded by a complete, generally thin, fibrous capsule. Histologically functioning nodules were formed by a mixture of micro- and macrofollicles, often with areas of hyperplasia. Collateral normal parenchyma was predominantly formed by macrofollicles.

Immunohistochemistry. In six of eight nodules (75%), the percentage of hNIS positive follicular cells was high (2++, between 40–80%); in the remaining two nodules, the positivity was moderately high (2+, 20%). Staining for hNIS was always confined to the cell membrane. In the normal surrounding thyroid tissue, the percentage of hNIS-positive follicular cells was in the range of 1–10%. hNIS staining was again confined to cell membrane.

Nonfunctioning thyroid nodules

Histology. Nonfunctioning thyroid nodules had the appearance of follicular adenomas surrounded by a complete fibrous capsule. In 10 cases, the capsule was thick, whereas in the others it was rather thin. The architecture was predominantly microfollicular, even if focal or diffuse macrofollicular areas were also observed. Some nonfunctioning nodules were solid-trabecular.

Immunohistochemistry. The results of hNIS immunoreactivity in nonfunctioning nodules are summarized in Table 2 and are shown in Fig. 1. Twelve of 22 (54%) benign nonfunctioning nodules showed an increased expression of hNIS protein with respect to the normal surrounding tissue. In 8 of 22 nodules (36%), the percentage of immunoreactive cells for hNIS was high (2++; between 30–80%). Among these eight nodules, four expressed hNIS protein in the cytoplasm only, and four both in the cytoplasm and at the cell membrane. The normal extranodular parenchyma showed 1–10% of hNIS-positive cells, and the staining was confined to the cell membrane. In 4 of 22 (18%) nonfunctioning nodules, the number of immunoreactive cells for hNIS was moderately high (2+; 15 and 20%). In one of these nodules, the location for hNIS immunoreactivity was both cytoplasmic and at the cell membrane, whereas in the remaining three nodules hNIS reactivity was present only in the cytoplasm. The normal extranodular parenchyma showed a percentage of positive cells ranging from 2–10%. hNIS staining was confined to the cell membrane only. Ten of 22 (45%) nonfunctioning nodules were negative for hNIS staining. The extranodular normal parenchyma contained 1–20% of positive cells. The location of hNIS immunoreactivity was confined to the cell membrane.

View larger version (162K): [in this window] [in a new window]   Figure 1. Immunohistochemical analysis of hNIS expression in benign nonfunctioning thyroid nodules and the surrounding normal thyroid tissue. A–C, Representative sections from nonfunctioning thyroid nodule. A, Thyroid follicular cells show diffuse, strong, mostly intracytoplasmic immunoreactivity for hNIS protein. B, Thyroid follicular cells show both cell membrane and intracytoplasmic immunoreactivity for hNIS protein. C, Thyroid follicular cells show a prevalent cell membrane immunoreactivity for hNIS protein but also intracytoplasmic immunoreactivity is present. D–F, Normal surrounding thyroid tissues. Few thyroid follicular cells show hNIS protein immunoreactivity, which is confined to cell membrane.

	Discussion

Top Abstract Introduction Patients and Methods Results Discussion References

 
Nonfunctioning thyroid nodules, in contrast to the rest of the gland, take up little or no radioiodine as shown by ¹³¹I scintigraphy (1). In the majority of nonfunctioning thyroid nodules, an iodide-trapping defect is detected (4), whereas in a minority an iodide organification defect can be found (5). The molecular mechanisms responsible for the iodide pump defect might be due to both an alteration in the primary structure of the hNIS protein and an alteration of its expression. Investigating the expression of hNIS gene or searching for somatic inactivating mutations of hNIS gene in nonfunctioning thyroid nodules acquires a peculiar relevance because defects of hNIS at any level might play a role in the poorly understood mechanisms leading to the growth of nonfunctioning thyroid nodules (16, 17). It is well established that thyroid growth and function are mainly controlled by the opposite actions of TSH and iodide (16, 17) both in vivo and in vitro. TSH stimulates whereas iodide inhibits thyroid cell proliferation (16, 17). Intracellular iodide, as such, exerts a negative control on growth of thyreocytes in vitro (16, 17), whereas iodine deficiency increases the sensitivity of thyreocytes to the growth-promoting effect of TSH (16, 17). The direct effect of iodide on thyroid cells has been studied in vitro using thyroid slices. Iodide has been shown to acutely inhibit both the adenylate-cyclase and the phospholipase-C cascades activated by the interaction of the TSH receptor with TSH (16, 17). These inhibitory effects are relieved by blocking iodide trapping and oxidation, suggesting that they are mediated by one or several intracellular iodinated intermediates, one of which is 2-iodohexadecanal (18). In the absence of iodide trapping or oxidation, the negative control of iodide on thyroid cell growth is relieved, thus giving a selective advantage for growth to affected thyroid cells; the appearance of new mutations and possibly tumor transformation may be favored also (16). To study the hNIS expression or the possible existence of structural defects in the hNIS protein in nonfunctioning thyroid nodules, we selected patients with isolated thyroid nodules that were unable to trap iodide in vivo, suggesting a possible iodide transport defect.

The results of this study indicate that, as expected, functioning thyroid nodules express a high level of hNIS protein with respect to the normal surrounding thyroid tissue. The location of immunoreactivity was confined to the cell membrane.

Nonfunctioning nodules showed a heterogeneous pattern of expression of hNIS protein. We observed that 54% of benign nonfunctioning nodules showed an increased expression of hNIS protein with respect to the normal surrounding tissue. In some of these nonfunctioning nodules, up to 80% of cells were stained positive for hNIS with respect to 1–10% of cells in the normal surrounding thyroid tissue. At variance with the cell membrane pattern observed in the normal extranodular tissue and in toxic thyroid adenomas, hNIS staining in nonfunctioning thyroid nodules was predominantly cytoplasmatic. In 46% of nonfunctioning nodules, no staining for hNIS protein was evident, suggesting a very low expression level, not detectable by immunohistochemistry.

In all nonfunctioning thyroid nodules, we also searched for somatic loss-of-function mutations of hNIS gene that might explain the defective targeting of the protein to the cell membrane. Germline loss-of-function mutations of the hNIS gene have been reported in patients with a rare inherited disorder of thyroid hormone biosynthesis characterized by an iodide transport defect (19, 20, 21). All of these patients had multinodular goiter with nonfunctioning nodules (19, 20, 21). However, in the present study none of the nonfunctioning nodules with either a high or low hNIS protein expression harbored a somatic gene mutation.

In a previous study, Joba et al. (10), using Northern blot and quantitative PCR, have shown very low levels of hNIS mRNA in the few nonfunctioning thyroid nodules they studied. The low level of hNIS mRNA was confirmed by a low immunoreactivity for the protein in the same nodules by immunohistochemistry (10). Similarly, low levels of hNIS mRNA were detected in 20 benign nonfunctioning adenomas by Arturi et al. (9). Caillou et al. (11), using a rabbit polyclonal hNIS antibody, failed to show an immunostaining for hNIS in the majority of follicles of six benign nonfunctioning adenomas.

In contrast to these studies, Northern blot analysis revealed a 3-fold increase in the level of hNIS mRNA in specimens of papillary thyroid carcinomas vs. specimens of normal thyroid tissue (22). In the same study, immunohistochemical staining using a rabbit polyclonal hNIS antibody revealed abundant hNIS in 8 of 12 carcinomas, whereas hNIS protein was barely detected in specimens of normal thyroid (22). Recently, similar results have been obtained by Dohan et al. (13) who clearly showed that 70% of malignant thyroid nodules exhibited increased hNIS protein expression with respect to the normal surrounding thyroid tissue using a polyclonal anti-hNIS antibody. Interestingly, hNIS was located either in the plasma membrane and intracellular compartment simultaneously or exclusively in intracellular compartments.

The results obtained in this study suggest that two possible mechanisms are responsible for defective iodide trapping of nonfunctioning thyroid nodules. Nearly half of the nodules showed a high expression of hNIS protein, which was retained in the cytoplasm, suggesting a possible defect in the targeting of the protein to the cell membrane. Genetic analysis did not show any modification of the genomic DNA of the hNIS gene, confirming that the primary structure of the protein was intact. It is conceivable that posttranscriptional, translational, and posttranslational alterations might be responsible for the defective targeting of hNIS to the cell membrane or an altered distribution to intracellular organelles (13). It has long been known that TSH stimulates thyroid I^- uptake by up-regulating NIS transcription via cAMP. Recently, Riedel et al. (23) showed that NIS function is also regulated by TSH at a posttranscriptional level. They showed that NIS is a phosphoprotein and that NIS phosphorylation pattern was regulated by TSH. In the absence of TSH, NIS was redistributed from the plasma membrane to intracellular compartments in FRTL-5 cells (23). In the remaining half of the nonfunctioning nodules included in the present investigation, immunohistochemistry failed to show any hNIS protein staining. Some of the mechanisms that might influence the level of expression of the NIS gene have been identified recently. Activation of rat thyroid NIS gene promoter by TTF-1 has been reported (24). After the cloning of the hNIS gene promoter, putative TTF-1 and Pax 8 binding sites were also identified. It was also shown that the thyroid transcription factor Pax 8 binds at two sites within the rat NIS enhancer (25), playing an important role in controlling NIS expression (25). Thus, genetic alterations interfering with Pax 8 binding might decrease transcriptional activity of the NIS upstream enhancer (25).

In conclusion, the results obtained in this study show that two mechanisms contribute to the reduced radioiodide uptake typical of benign nonfunctioning thyroid nodules: 1) reduced expression of the NIS protein, and 2) defective targeting of hNIS to the cell membrane.

	Acknowledgments

 
We thank Dr. S. Costagliola and Dr. G. Vassart (Institut de Recherche Interdisciplinaire en Biologie Humaine et Nucléaire, Brussels, Belgium) for kindly providing the hNIS monoclonal antibody.

	Footnotes

 
This work was supported by the following grants: Ministero dell’Università e della Ricerca Scientifica (MURST) Programma di Ricerca, Meccanismi molecolari nella patogenesi del nodulo tiroideo; MURST Programma di Ricerca, Strategie per la valutazione degli effetti disruptivi dei contaminanti ambientali sul sistema endocrino degli animali e dell’uomo; and Consiglio Nazionale delle Richerche Progetto Biotecnologie CTB 99.00.224. PF 31, Basi molecolari delle neoplasie benigne e maligne della tiroide.

Abbreviations: hNIS, Human NIS; NIS, sodium iodide symporter.

Received August 2, 2001.

Accepted October 9, 2001.

	References

Top Abstract Introduction Patients and Methods Results Discussion References

 

1. Mazzaferri EL 1993 Management of a solitary thyroid nodule. N Engl J Med 328:553–559[Free Full Text]
2. Belfiore A, Rosa GL, Giuffrida D, Regalbuto C, Lupo L, Fiumara A, Ippolito O 1995 The management of thyroid nodules. J Endocrinol Invest 18:155–158[Medline]
3. Wiener JD 1987 Plummer’s disease: localized thyroid autonomy. J Endocrinol Invest 10:207–224[Medline]
4. Field JB, Larsen PR, Yamashita K, Mashiter K, Dekker A 1973 Demonstration of iodide transport defect but normal iodide organification in nonfunctioning nodules of human thyroid gland. J Clin Invest 52:2404–2410
5. Demeester-Mirkinf N, Van Sande J, Corvilan J, Dumont JE 1975 Benign thyroid nodule with normal iodide trap and defective organification. J Clin Endocrinol Metab 41:1169–1171[Abstract/Free Full Text]
6. Dai G, Levy O, Carrasco N 1996 Cloning and characterization of the thyroid iodide transporter. Nature 379:458–460[CrossRef][Medline]
7. Smanik PA, Liu Q, Furminger TL, Ryu K, Xing S, Mazzaferri EL, Jhiang SM 1996 Cloning of the human sodium iodide symporter. Biochem Biophys Res Commun 226:339–345[CrossRef][Medline]
8. Levy O, Vieja A, Carrasco N 1998 The Na⁺I^- symporter (NIS): recent advances. J Bioenerg Biomembr 30:195–206[CrossRef][Medline]
9. Arturi F, Russo D, Schlumberger M, du Villard JA, Caillou B, Vigneri P, Wicker R, Chiefari E, Suarez HG, Filetti S 1998 Iodide symporter gene expression in human thyroid tumors. J Clin Endocrinol Metab 83:2493–2496[Abstract/Free Full Text]
10. Joba W, Spitzweg C, Schriever K, Heufelder AE 1999 Analysis of human/iodide symporter, thyroid transcription factor-1, and paired-box-protein-8 gene expression in benign thyroid diseases. Thyroid 9:455–466[Medline]
11. Caillou B, Troalen F, Baudin E, Talbot M, Filetti S, Schlumberger M, Bidart JM 1998 Na⁺/I^- symporter distribution in human thyroid tissues: an immunohistochemical study. J Clin Endocrinol Metab 83:4102–4106[Abstract/Free Full Text]
12. Lazar V, Bidart JM, Caillou B, Mahe C, Lacroix L, Filetti S, Schlumberger M 1999 Expression of the Na⁺/I^- symporter gene in human thyroid tumors: a comparison study with other thyroid-specific genes. J Clin Endocrinol Metab 84:3228–3234[Abstract/Free Full Text]
13. Dohan O, Baloch Z, Banrevi Z, Livolsi V, Carrasco N 2001 Predominant intracellular overexpression of the Na⁺/I^- symporter (NIS) in a large sampling of thyroid cancer cases. J Clin Endocrinol Metab 86:2697–2700[Abstract/Free Full Text]
14. Pohlenz J, Duprez L, Weiss RE, Vassart G, Refetoff S, Costagliola S 2000 Failure of membrane targeting causes the functional defect of two mutant sodium iodide symporters. J Clin Endocrinol Metab 85:2366–2369[Abstract/Free Full Text]
15. Tonacchera M, Vitti P, Agretti P, Ceccarini G, Perri A, Cavaliere R, Mazzi B, Naccarato AG, Viacava P, Miccoli P, Pinchera A, Chiovato L 1999 Functioning and nonfunctioning thyroid adenomas involve different molecular pathogenetic mechanisms. J Clin Endocrinol Metab 84:4155–4158[Abstract/Free Full Text]
16. Dumont JE, Lamy F, Roger P, Maenhaut C 1992 Physiological and pathological regulation of thyroid cell proliferation and differentiation by thyrotropin and other factors. Physiol Rev 72:667–697[Free Full Text]
17. Uyttersprot N, Pelgrims N, Carrasco N, Gervy C, Maenhaut C, Dumont JE, Miot F 1997 Moderate doses of iodide in vivo inhibit cell proliferation and the expression of thyroperoxidase and Na⁺I^- symporter mRNAs in dog thyroid. Mol Cell Endocrinol 131:195–203[CrossRef][Medline]
18. Panneels V, Van Sande J, Van den Bergen H, Jacoby C, Braekman JC, Dumont JE, Boeynaems JM 1994 Inhibition of human thyroid adenyl cyclase by 2-iodoaldehydes. Mol Cell Endocrinol 106:41–50[CrossRef][Medline]
19. Fujiwara H, Tatsumi K, Miki K, Harada T, Miyai K, Takai S, Amino N 1997 Congenital hypothyroidism caused by a mutation in the Na⁺I^- symporter. Nat Genet 16:124–125[CrossRef][Medline]
20. Matsuda A, Kosugi S 1997 A homozygous missense mutation of sodium/iodide symporter gene causing iodide transport defect. J Clin Endocrinol Metab 82:3966–3971[Abstract/Free Full Text]
21. Pohlenz J, Medeiros-Neto G, Gross JL, Silveiro SP, Knobel M, Refetoff S 1997 Hypothyroidism in a Brazilian kindred due to iodide trapping defect caused by a homozygous mutation in the sodium/iodide symporter gene. Biochem Biophys Res Commun 240:488–491[CrossRef][Medline]
22. Saito T, Endo T, Kawaguchi A, Ikeda M, Katoh R, Kawaoi A, Muramatsu A, Onaya T 1998 Increased expression of the sodium/iodide symporter in papillary thyroid carcinomas. J Clin Invest 101:1296–1300[Medline]
23. Riedel C, Levy O, Carrasco N 2001 Post-transcriptional regulation of the sodium/iodide symporter (NIS) by thyrotropin. J Biol Chem 276:21458–21463[Abstract/Free Full Text]
24. Endo T, Kaneshige M, Nakazato M, Ohmori N, Harii N, Onaya T 1997 Thyroid transcription factor-1 activates the promoter activity of rat Na⁺I^- thyroid symporter gene. Mol Endocrinol 11:1747–1755[Abstract/Free Full Text]
25. Ohno M, Zannini M, Levy O, Carrasco N, Di Lauro R 1999 The paired-domain transcription factor Pax 8 binds to the upstream enhancer of the rat sodium/iodide symporter gene and participates in both thyroid-specific and cyclic-cAMP-dependent transcription. Mol Cell Biol 19:2051–2060[Abstract/Free Full Text]

This article has been cited by other articles:

				I. Peyrottes, V. Navarro, A. Ondo-Mendez, D. Marcellin, L. Bellanger, R. Marsault, S. Lindenthal, F. Ettore, J. Darcourt, and T. Pourcher Immunoanalysis indicates that the sodium iodide symporter is not overexpressed in intracellular compartments in thyroid and breast cancers Eur. J. Endocrinol., February 1, 2009; 160(2): 215 - 225. [Abstract] [Full Text] [PDF]

				D. D. Vadysirisack, E. S.-W. Chen, Z. Zhang, M.-D. Tsai, G.-D. Chang, and S. M. Jhiang Identification of in Vivo Phosphorylation Sites and Their Functional Significance in the Sodium Iodide Symporter J. Biol. Chem., December 21, 2007; 282(51): 36820 - 36828. [Abstract] [Full Text] [PDF]

				D. D. Vadysirisack, D. H. Shen, and S. M. Jhiang Correlation of Na+/I- Symporter Expression and Activity: Implications of Na+/I- Symporter as an Imaging Reporter Gene J. Nucl. Med., January 1, 2006; 47(1): 182 - 190. [Abstract] [Full Text] [PDF]

				Z. Zhang, Y.-Y. Liu, and S. M. Jhiang Cell Surface Targeting Accounts for the Difference in Iodide Uptake Activity between Human Na+/I- Symporter and Rat Na+/I- Symporter J. Clin. Endocrinol. Metab., November 1, 2005; 90(11): 6131 - 6140. [Abstract] [Full Text] [PDF]

				K. Krohn, D. Fuhrer, Y. Bayer, M. Eszlinger, V. Brauer, S. Neumann, and R. Paschke Molecular Pathogenesis of Euthyroid and Toxic Multinodular Goiter Endocr. Rev., June 1, 2005; 26(4): 504 - 524. [Abstract] [Full Text] [PDF]

				A. C F Ferreira, L. P Lima, R. L Araujo, G. Muller, R. P Rocha, D. Rosenthal, and D. P Carvalho Rapid regulation of thyroid sodium-iodide symporter activity by thyrotrophin and iodine J. Endocrinol., January 1, 2005; 184(1): 69 - 76. [Abstract] [Full Text] [PDF]

				S. Trouttet-Masson, S. Selmi-Ruby, F. Bernier-Valentin, V. Porra, N. Berger-Dutrieux, M. Decaussin, J.-L. Peix, A. Perrin, C. Bournaud, J. Orgiazzi, et al. Evidence for Transcriptional and Posttranscriptional Alterations of the Sodium/Iodide Symporter Expression in Hypofunctioning Benign and Malignant Thyroid Tumors Am. J. Pathol., July 1, 2004; 165(1): 25 - 34. [Abstract] [Full Text] [PDF]

				X. Lin, A. H. Fischer, K.-y. Ryu, J.-y. Cho, T. J. Sferra, R. T. Kloos, E. L. Mazzaferri, and S. M. Jhiang Application of the Cre/loxP System to Enhance Thyroid-Targeted Expression of Sodium/Iodide Symporter J. Clin. Endocrinol. Metab., May 1, 2004; 89(5): 2344 - 2350. [Abstract] [Full Text] [PDF]

				I. L. Wapnir, M. van de Rijn, K. Nowels, P. S. Amenta, K. Walton, K. Montgomery, R. S. Greco, O. Dohan, and N. Carrasco Immunohistochemical Profile of the Sodium/Iodide Symporter in Thyroid, Breast, and Other Carcinomas Using High Density Tissue Microarrays and Conventional Sections J. Clin. Endocrinol. Metab., April 1, 2003; 88(4): 1880 - 1888. [Abstract] [Full Text] [PDF]

				O. Dohan, A. De la Vieja, V. Paroder, C. Riedel, M. Artani, M. Reed, C. S. Ginter, and N. Carrasco The Sodium/Iodide Symporter (NIS): Characterization, Regulation, and Medical Significance Endocr. Rev., February 1, 2003; 24(1): 48 - 77. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tonacchera, M. Articles by Vitti, P. Search for Related Content PubMed PubMed Citation Articles by Tonacchera, M. Articles by Vitti, P. Pubmed/NCBI databases Substance via MeSH Medline Plus Health Information Thyroid Cancer