ABSTRACT
Objective To investigate BRAFV600E mutation and sodium iodide symporter (NIS) expression and its clinical significance in papillary thyroid carcinomas (PTC).Methods BRAFV600E mutation was evaluated by direct sequencing and BRAFV600E mutation was determined in 40 cases of PTC.NIS expression was examined by means of immunohistochemistry.The relationship between BRAFV600E mutation and the clinicopathologic features of PTC was analyzed.The relationship between NIS expression and BRAFV600E mutation in PTC was analyzed.Results Positive BRAFV600E mutation was determined in 23 of 40 cases of PTC (57.5％),whereas positive NIS expression was showed in 7 of 40 cases (12.5％).BRAFV600E mutation was associated with extrathyroid invasion and a high risk of disease recurrence in PTC (P ＜ 0.05).Positive NIS expression was found in only one of 23 cases of PTC with BRAFV600E mutation,and positive NIS expression was associated with a statistically significant lower BRAFV600E mutation in PTC (P =0.011).Conclusions BRAFV600E mutation might be associated with higher aggressiveness,higher disease recurrence and a poorer prognosis.Lower NIS expression may be responsible for poor 131I uptake in
ABSTRACT
The expression of Rap1 GAP protein was detected in 69 cases of papillary thyroid carcinoma and adjacent normal thyroid tissues with immunohistochemistry method.Methylation of Rapl GAP gene was analyzed by methylation-specific-PCR (MSP) in these tissues.The immunohistochemistry results indicated that the Rap1GAP protein was down-regulated in tumor tissues of 54 ( 78％ ) cases compared with normal thyroid tissues.Statistical analysis demonstrated that the decreased level of Rap1 GAP protein expression was significantly correlated with the tumor stage T according to American Joint Committee on Cancer ( AJCC,P =0.043 ).The MSP results demonstrated that 46 cases of Rap1GAP gene methylation were detected in 54 cases with down-regulated expression of Rap1GAP (66.7％),but only 1 case of methylation was found in 15 cases without obvious change of Rap1GAP expression (6.67％),showing significant difference ( P＜0.01 ).There was no methylation in normal thyroid tissues.These results suggest that raised methylation of promoter region may contribute to the low expression of Rap1GAP protein in papillary thyroid carcinoma.