Alterations of NIS expression in functioning thyroid nodules.
OBJECTIVE
This study aimed to analyze both the level and the cell site of the sodium-iodide symporter (NIS) protein expression in autonomously functioning thyroid nodules (AFTNs) and extranodular thyroid tissues. In addition, this study sought to compare the clinical results of patients with the levels of human NIS (hNIS) protein expression.


METHODS
The histological slides consisted of 36 AFTNs and 31 extranodular thyroid tissues from 28 patients (5 males, 23 females; mean age 54.5±11.0 years; range 37 to 72 years) who underwent surgery for toxic multinodular goitre. The expression of NIS protein was investigated by immunohistochemistry in paraffin-embedded tissue sections using anti-hNIS monoclonal antibody by the labeled streptavidin-biotin method.


RESULTS
The percentage of hNIS positive follicular cells was significantly higher in the AFTNs (13.33±12.09) than in the extranodular thyroid tissues (1.35±3.03). Staining for hNIS was mostly confined to the cell membrane in the AFTNs (88.9%) and in the extranodular thyroid tissues (54.5%). The clinical parameters and nodule volume did not establish any correlation with hNIS immunoreactivity.


CONCLUSIONS
Our data indicate that functioning nodules express higher amounts of NIS protein than the extranodular thyroid tissue, but the level of hNIS immunoreactivity was lower than had been reported in the previous literature. This result may be due to interindividual variability between different populations, and iodine status. Furthermore, the localization of the NIS protein might not give an indication of its functional status.
Department of Endocrinology, Dr. Lütfi Kırdar Kartal Training and Research Hospital, İstanbul, Turkey.
Hülya Ilıksu
HI
Gözü
Dilek
D
Yavuzer
Handan
H
Kaya
Selahattin
S
Vural
Haluk
H
Sargın
Cem
C
Gezen
Mehmet
M
Sargın
Sema
S
Akalın
D000328:Adult; D000368:Aged; D005260:Female; D005786:Gene Expression Regulation; D006044:Goiter, Nodular / Q000601:surgery*; D006801:Humans; D007150:Immunohistochemistry; D007455:Iodine / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D027981:Symporters / Q000235:genetics* / Q000378:metabolism; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000378:metabolism; D016606:Thyroid Nodule / Q000378:metabolism*; D013965:Thyroidectomy; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014158:Transcription, Genetic; D014284:Triiodothyronine / Q000097:blood; D000099209:Sodium-Iodide Symporters
D007455:Iodine; D027981:Symporters; D013972:Thyrotropin; D013974:Thyroxine; D014284:Triiodothyronine; D000099209:Sodium-Iodide Symporters