Research Of The Mutation Of APC Gene,β-catenin Gene And Their Diagnostic Value In Thyroid Tumors

Objectives:Wnt signaling pathway plays a critical role on cell growth and proliferation, and disturbances of the Wnt signal transduction pathway were significantly related to human tumor transformation. This project was designed to understand the relationship between APC,β-catenin,Galectin-3and the occurrence,progression metastasis of thyroid tumor, and to find out diagnostic markers between benign and malignant thyroid tumor for the diagnosis of clinicopathological features.Methods:The expression of APC,β-catenin and Galectin-3protein in31cases of nodular goiter,65cases of differentiated thyroid carcinoma and10cases of normal thyroid tissues(Control group) were detected by S-P immunohistochemical technique, and the mutation of APC and p-catenin gene were screened by Direct Sequencing.Results:(1) The protein expression level of Galectin-3in differentiated thyroid carcinoma was83.03%that was significantly higher than nodular goiter (19.35%) and normal thyroid tissues(0%)(P<0.01);(2) APC gene and expression of APC protein appear normal in benign and malignant thyroid tumor(P>0.05).(3) There was no aberrant expression of β-catenin protein in normal thyroid tissues, while abnormal expression presented in differentiated thyroid cancinoma and nodular goiter, the aberrant rates were72.31%(47/65) and32.25%(10/31) respectively, which has statistical significance(P<0.01).(4) In combined determination of Galectin-3and β-catenin, the abnormal expression of them in differentiated thyroid cancinoma and nodular goiter were86%and25%respectively(P<0.05), and the expression of Galectin-3was significant correlated to the aberrant expression of β-catenin in65cases of differentiated thyroid carcinoma (P<0.05).(5) The abnormal expression of β-catenin was closely related to lymph node metastasis(P<0.05), the expression rates in cases with lymph node metastasis and cases without lymph node metastasis were90%and64.44%respectively.(6)19cases out of65cases of differentiated thyroid carcinoma showed β-catenin exon3gene mutation and their mutation occurred at codon37and codon45, there was no mutation in31cases of nodular goiter(P<0.01), The mutation of β-catenin exon3gene was closely related to lymph node metastasis(P<0.05);19cases out of47cases with β-catenin protein abnormal expression showed β-catenin gene mutation while there was no mutation in cases with normal expression, the mutation of β-catenin gene was significant correlated to the abnormal expression of β-catenin protein (P<0.05).Conclusion:(1) There was a significant difference of positive expression rate of Galectin-3between differentiated thyroid carcinoma and nodular goiter, and Galectin-3had the potential to be a diagnostic marker in thyroid tumor.(2) There was no relationship between APC and thyroid tumor transformation.(3) β-catenin can be used as a valuable marker for benign and malignant thyroid tumor, its expression was contributed to deterioration of thyroid cancer; and detection of β-catenin gene mutation was beneficial to diagnose thyroid cancer.(4) The mutation of β-catenin exon3gene was contributed to abnormal expression of β-catenin protein.(5) Combined detection of β-catenin and Galectin-3protein in thyroid tissue was useful for the diagnosis of thyroid cancer.