| Objective: Thyroid cancer incidence rates have significantly increased in recent years in China, especially papillary thyroid microcarcinoma.BRAFV600 E mutation was the most common molecular genetic alterations of thyroid cancer.Real-time fluorescent quantitative PCR was performed for detection of BRAFV600 E mutation in PTMC in the study,at the same time immunohistochemistry(IHC) using a BRAF mutation-specific antibody(VE1) was performed for detection of BRAFV600 E mutated protein of PTMC.The aim of this study was to evaluate the BRAFV600 E gene mutational status and the expression of VE1 antibody,and analyze their association with clinicopathologic parameters,and provid the important evidence for diagnosis,differential diagnosis and judgment of prognosis. Methods: The study collected 100 cases of paraffin embed tissue of PTMC and the cases of benign and malignant thyroid lesion as control(including 50 cases of PTC,20 cases of thyroid adenoma, 10 cases of normal tissue beside carcinoma). All of the samples were taken from the department of pathology of the Fuzhou General Hospital of Nanjing Military Command and 175 Hospital of People’s Liberation Army between 2010 and 2015,and were histological observed and diagnosed by two high qualification pathologist.Real-time fluorescent quantitative PCR was performed for detection of BRAFV600 E mutation in PTMC,at the same time immunohistochemistry(IHC) using a BRAF mutation-specific antibody(VE1) was performed for detection of BRAF mutated protein of PTMC. In the study we evaluated the BRAF gene mutational status between PTMC and PTC.We also analyzed the relationship between the BRAFV600 E mutation and the expression of VE1 and their clinicopathological parameters,and the correlation between the BRAFV600 E mutation and the expression of VE1. Results: ①BRAFV600E mutation was found to be present in 54(54.0%) of 100 patients with PTMC,while BRAFV600 E mutation was found to be present in 37(74.0%) of 50 patients with PTC. However,benign thyroid lesions in control(20 cases of thyroid adenoma and 10 cases of normal tissue beside carcinoma) were negative for BRAFV600 E mutation. The data of 100 cases of PTMC and 50 cases of PTC integrated, the presence of the BRAFV600 E mutation was significantly associated with tumor size,but not with age,gender,single or multiple lesions,lymph node metastasis,thyroidal invasion,concurrent dieases, recurrence. ②A BRAF mutated protein was detected using IHC method in 74 cases of PTMC. 37(50%) cases of PTMC were positive for the BRAF mutated protein by IHC. On the contrary, 20 cases of thyroid adenoma and 10 cases of normal tissue beside carcinoma were negative for BRAF mutated protein. The BRAF protein expression was significantly associated with tumor size,but not with age,gender,single or multiple lesions,lymph node metastasis,thyroidal invasion,concurrent dieases, recurrence. ③In this study,the concordance rate between immunohistochemistry(IHC) and PCR method was 78.38%(58/74) for VE1(K=0.568,P =0.000).Compared with real-time fluorescent quantitative PCR,the gold standard for statistical analysis,7 false-positive and 9 false-negative VE1 IHC cases remained,resulting in a sensitivity of 76.9% and a specificity of 80.0%. Conclusions: More than half of PTMC harbored BRAFV600 E mutations.Real-time fluorescent quantitative PCR was a effective method for detection of BRAFV600 E mutation.IHC using the VE1 antibody represented a feasible approach for evaluating BRAF mutation status,comparing with real-time fluorescent quantitative PCR.Both methods could effectively distinguish PTMC,thyroid adenoma and normal thyroid tissue.The detection of BRAFV600 E mutations was contribute to the diagnosis and differential diagnosis of PTMC. |
