BRAFV600E Gene Mutation And Expressions Of Sodium Iodide Symporter And Its Clinical Significance In Papillary Thyroid Carcinomas

ObjectTo investigate BRAFV600E gene mutation and expressions of sodium iodide symporter and its clinical significance in papillary thyroid carcinomas.Methods40cases of paraffin embed tissue of papillary thyroid carcinomas from January2006to December2006in the First Affiliated Hospital College of Medicine, Zhejiang University were collected. The BRAFV600gene mutation was evaluated by direct sequencing and the BRAFV600E gene mutation was determined. Furthermore, the relationship between BRAF gene mutation and the clinicopathologic features of papillary thyroid carcinomas was analyzed. The expressions of NIS protein were examined by means of immunohistochemistry and the relationship between expressions of NIS protein and the BRAFV600E gene mutation in papillary thyroid carcinomas was analyzed.ResultsThe BRAFv600E gene mutation positive was determined in23of40cases of papillary thyroid carcinomas(57.5%), whereas the BRAFv600E gene mutation negative in23of40cases (42.5%). BRAFV600E gene mutation was not associated with age, gender, tumour size, the presence of lymph node metastasis, TMN stages T and N, and advanced TMN stages, but associated with extrathyroid invasion and a high risk of disease recurrence. NIS protein was expressed on the basolateral membrane in positive control-Grave disease tissue, and showed no staining in negative control. Negative NIS protein expression was showed in33of40cases of papillary thyroid carcinomas(87.5%), whereas positive NIS protein expression was showed in7of40cases(12.5%). Positive NIS protein expression was found in one of23cases of papillary thyroid carcinomas with BRAFV600E gene mutation and positive NIS protein expression was associated a statistically significant lower BRAFV600E mutation in papillary thyroid carcinomas(P=0.011).ConclusionsOur results confirmed that, BRAFV600E gene mutation is significantly high in papillary thyroid carcinomas, and BRAFV600E gene mutation might be associated with more aggressiveness, higher disease recurrence and a poor prognostic outcome. Defective targeting of NIS protein to the plasma membrane or its retention at the cytoplasm is in most papillary thyroid carcinoma. Furthermore, BRAFV600E mutation, causing less NIS-mediated131I uptake, might be attributable to a lower functional NIS protein expression in papillary thyroid carcinomas. Our current study appears to be valuable for predicting prognosis and important clinical significance of surgery operation and131I treatment in patients with papillary thyroid carcinomas.