The Clinic Investigation Of BRAF Gene Mutation In The Papillary Thyriod Cancer

Objective To evaluate the correlation with BRAF gene mutation and the clinicopathological parameters of PTC in GuangXi. Thus it could raise the level of clinical diagnosis in PTC. Further provide objective basis for the prognosis of PTC. And explore a new therapy target aim to the BRAF gene by molecular-biology.Methods Collected 60 cases of paraffin embed tissue of PTC and 20 cases of benign thyroid lesion as control(10 cases of nodular goiter and 10 cases of thyroid adenoma) from January 2004 to January 2008 in the first affiliated hospital of Guang Xi medical university. Genomic DNA was extracted from the paraffin-fixed slices by FFPE DNA Kit from Omega Co. Then analyzed DNA samples for mutation in BRAF exon 15 by PCR, and also utilized SSCP(Single Strand Conformation Polymorphism, SSCP) analysis to identify abnormal staining bands,then the corresponding bands was sequenced directly. Finally, analyzed the significance of BRAF gene mutation in thyroid cancer and benign control cases, and also analyzed the relationship between the BRAF gene mutation and the clinicopathological parameters of PTC by using stastical softerware SPSS 13.0.The statistical method is chi-square test,and the level of test is 0.05.Results 1. The ratio of BRAF gene mutation rate in PTC tissue was 56.7% (34/60), whereas it was 0%(0/20) in benign thyroid lesions. The ratio of BRAF mutation in PTC tissues was significantly higher than that of benign thyroid lesions. The two groups was significant difference byχ2 test (χ2 = 19.710, P <0.001). DNA bidirectional sequencing confirmed missense mutations,which is exon 15 single nucleotide missense mutation (T1799A). 2. The ratio of BRAF gene mutation with no significant difference between the groups of gender (χ2 = 0.090, P> 0.05); between the groups of age (≥45 years or <45 years),the difference was significantly (χ2 = 5.621, P <0.05 ); between the groups of tumor size (≥2cm or <2cm) the difference was not statistically significant (χ2=2.241, P>0.05); between the pathological subtype group (classic, follicular subtype, high-cell type), the difference was significantly (χ2= 8.136, P <0.05); the ratio of BRAF gene mutations in adjacent tissues violations group was significantly higher than without violations,difference between the two groups was significant (χ2= 7.483, P <0.05); between the group with or without lymph node metastasis, the difference was significant (χ2=4.671, P<0.05); in clinical stage groups (Ⅰ~ⅡorⅢ~Ⅳ), the ratio of the BRAF gene mutation in the group ofⅢ~Ⅳwas significantly higher than the group ofⅠ~Ⅱ, the difference between the two groups was significant (χ2= 6.275, P <0.05); between the group of postoperative recurrence and the non-recurrence, the difference was no statistically significant (χ2= 4.477, P> 0.05).Conclusions 1. BRAF gene mutation has a high detection rate in PTC in Guang Xi, compared with benign thyroid tumor, indicating that BRAF mutation can be used as a molecular marker in differentiating PTC and benign thyroid tumor. 2. The BRAF gene mutation has a close relationship with the clinical pathology characteristics of PTC, it may be taken as a new standard to detect and post-operationally evaluate the PTC risk factors.