Expression of Bmi-1 gene in papillary thyroid carcinoma

Abstract

Objective To analyze expression of Bmi-1 gene in thyroid tissues and the relationship between Bmi-1 gene and metastasis of papillary thyroid carcinoma.Methods RT-PCR was used to detect expression of Bmi-1 in normal thyrroid tissues(8 eases),nodular goiters(18 cases)and papillary thyroid carcinomas (24 cases).The result was analyzed by Fisher exact propability test.Results Bmi-1 expression was detected only in 1 case(12.5%)in normal thyroid tissues group,3 cases(16.7%)in nodular goiters group,and 19 cases(79.2%)in papillary thyroid carcinoma group.The difference of Bmi-1 expression between the 3 groups had statistical significance(P<0.05).There were 16 cases of lymph node metastasis(66.67%)in the 24 cases of papillary thyroid carcinoma.The difference of Bmi-1 expression between cases with cervical lymph node metastasis and those without metastasis had statistical significance(P<0.05).Among the 19 thyroid carcinoma cases in which Bmi-1 expression was positive,12 eases(63.2%)were over45 years old,and 7 cases(36.8%)were under 45 years.The difference had statistical significance(P<0.05).Conclusions Expression of Bmi-1 gene in papillary thyroid carcinoma tissue is significantly higher than that in nodular goiters and normal thyroid tissues.Bmi-1 expression is closely relevant to lymph node metastasis and age,implying that Bmi-1 expression has clinical significance of distinguishing thyroid malignant tumors from benign diseases and it may provide clues to unravel the mechanism and prognosis of papillary thyroid carcinoma metastasis. Key words: Bmi-1 gene; Papillary thyroid carcinoma; Nodular goiter; Normal thyroid