A novel loss-of-function deletion in sodium/iodide symporter gene in follicular thyroid adenoma.
The sodium/iodide symporter (NIS) actively transports iodide into thyrocytes. However, in thyroid carcinoma, down-regulated or mis-targeted NIS expression is commonly found and usually correlates with tumor dedifferentiation and loss of radioiodine uptake capacity. In this study, we screened NIS genes of thyroid tumor tissues from three patients with thyroid carcinoma by using reverse transcription-polymerase chain reaction and nucleotide sequencing. We found a novel exon 6 deletion in NIS gene. We then examined the NIS gene from the blood of this patient. The nucleotide sequences of the flanking region of exon 6 were normal. By transient transfection and I-125 uptake assay, we found that the wild type NIS-expressing HepG2 cells accumulated six times more iodide than mutant and mock HepG2 cells. Our data demonstrated that the exon 6 deletion causes an iodide-trapping defect.
Liang
Ji-An
JA
Department of Radiation Therapy and Oncology, China Medical University Hospital, Taichung, Taiwan, ROC.
Chen
Chun-Ping
CP
Huang
Shin-Jer
SJ
Ho
Tin-Yun
TY
Hsiang
Chien-Yun
CY
Ding
Hueisch-Jy
HJ
Wu
Shih-Lu
SL
D000236:Adenoma / Q000235:genetics* / Q000503:physiopathology; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000473:pathology; D004252:DNA Mutational Analysis; D005091:Exons; D006801:Humans; D007454:Iodides / Q000493:pharmacokinetics; D007457:Iodine Radioisotopes; D008113:Liver Neoplasms / Q000473:pathology; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D027981:Symporters / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000503:physiopathology; D014162:Transfection; D014407:Tumor Cells, Cultured; D000099209:Sodium-Iodide Symporters
D007454:Iodides; D007457:Iodine Radioisotopes; D027981:Symporters; D000099209:Sodium-Iodide Symporters