ABSTRACT
Purpose To investigate the expression of insulin-like growth factor Ⅱ mRNA-binding protein 3 (IMP3) and its differential diagnostic significance in benign and malignant thyroid tumor. Methods The fluorescent quantitative PCR and immunohistochemical staining were used to detect the IMP3 expression in 71 cases of thyroid tissue of different pathological types. The differential diagnostic significance of IMP3 expression in benign and malignant thyroid tumor was analyzed. Results Compared with normal thyroid tissue, thyroid tumors including follicular variant of papillary thyroid carcinoma (FVPTC ), follicular thyroid carcinoma (FTC), papillary thyroid carcinoma(PTC), nodular goiter (NG), and follicular adenoma (FA) had significantly higher IMP3 mRNA expression levels with10.13, 8.81, 8.52, 2.46, and 1.49 holds, respectively. The positive expression rate of IMP3 protein in thyroid tumors were significantly higher, with the positive rate from high to low was FTC (100％ ), PTC (96.77％ ), FVPTC (90％ ), FA(20％ ), and NG (0). The expression level of IMP3 protein was positively correlated with the expression of mRNA (P＜0.01). The IMP3 expression level of malignant thyroid tumor(8.82 holds) was significantly higher than that of benign thyroid tumor (1.94 holds) (P＜0.01). The IMP3 expression level of malignant thyroid follicular lesions (9.36 holds) was higher than that of benign thyroid follicular lesions (1.49 holds) (P＜0.01). Conclusion IMP3 may be an effective and useful molecular maker for diagnosis of benign and malignant thyroid neoplasms, as well as the differential diagnosis between benign and malignant thyroid follicular lesions.