Expression of the sodium iodide symporter in differentiated thyroid cancer: clinical evidence.
OBJECTIVE
Molecular analysis of the expression of the sodium iodide symporter (NIS) in 32 patients with differentiated thyroid cancer (DTC) and correlation with scintigraphic findings ((131)I,(123)I) in 19 (59.4%) of them.


METHODS
NIS expression of 27 primary tumours, 13 lymphnodes and 18 distant metastases was determined by immunostaining using a murine monoclonal anti-NIS-antibody. NIS expression and radionuclide uptake of metastases were analysed by a semiquantitative visual score. Patients were divided into two subgroups: Group 1 (n = 8 patients): indirect correlation of radioiodine uptake (RIU) of subsequent metastases with NIS expression of 7 primary tumours and 3 metastases; Group 2 (n=11 patients): direct correlation of radionuclide uptake with NIS expression of 19 metastases which were excised after imaging.


RESULTS
49 of 58 specimens (84.5%) were NIS-positive. A preserved NIS-expression was found in 12 primary tumours and 8 of 10 (80%) synchrone and 6 of 7 (85.7%) metachrone metastases. Group 1 revealed a 100% positive predictive value (PPV) of a preserved NIS expression in the primary tumour regarding radioiodine uptake in metastases while a lack of NIS expression in the primary tumor did not reliable predict a loss of the metastases' ability to concentrate radioiodine. In group 2, only 11 of 19 (57.9%) specimens showed a concordant NIS expression and RIU whereas in the remaining 8 cases without visible RIU NIS expression was still present.


CONCLUSIONS
NIS expression of the primary tumour and metastases in DTC is usually well preserved. We found a positive correlation between NIS expression of the primary and metastatic tissue but could not identify such well correspondence between NIS expression and the RIU of subsequent metastases.
Schmitz
G
G
Department of Nuclear Medicine, Georg August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
Füzesi
L
L
Struck
J
J
Siefker
U
U
Hamann
A
A
Sahlmann
C-O
CO
Hüfner
M
M
Meller
J
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D027981:Symporters / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D013972:Thyrotropin / Q000097:blood; D000099209:Sodium-Iodide Symporters
D019788:Fluorodeoxyglucose F18; D019275:Radiopharmaceuticals; D027981:Symporters; D013972:Thyrotropin; D000099209:Sodium-Iodide Symporters