Analysis Of Lymph Node Metastasis Factors In Papillary Thyroid Microcarcinoma And BRAF^V600E Mutation Gene?PKM2?LDHA In The Expression Of Thyroid Carcinoma

Objective:In recent years,the incidence of papillary thyroid carcinoma?PTMC?has been growing rapidly.Although PTMC has an indolent behavior and a good prognosis after standardized treatment,a number of them can occur lymph node metastasis in early time.Here we would focus on exploring the risk factors for lymph node metastasis,including both central lymph node metastasis?CLNM?and lateral lymph node metastasis?LLNM?,to provide precise surgery to those PTMC patients.BRAF^V600E gene mutation is an important molecular event in the development of PTMC.In this study,we examined the status of BRAF mutation and further to uncover the relevance between BRAF^V600E status and clinical features in PTMC.Many tumor cells predominantly generate energy through high rates of glycolysis.In this study,the key enzymes PKM2 and LDHA were selected to detect the expression of these enzymes in papillary thyroid carcinomaand their relationship with clinicopathological features.Methods:The study is divided into three parts.In the first part,1587 patients with PTMC who underwent thyroid surgery in Tianjin Medical University Cancer Hospital from January 2013 to December 2015 were selected.The histopathological features of the patients were analyzed retrospectively.Univariate analyses were used to compare cervical LNM to clinicopathological features such as gender,age,tumor size,Hashimoto thyroiditis,extrathyroidal extension,multifocal,bilateralism and pathological subtype.Multivariate logistic regression analysis was performed to assess independent factors for cervical LNM with the factors screened by univariate analysis with P<0.05.In the second part,collected a total of 299 cases of the paraffin-embedded tissue from January 2016 to December 2016 performed surgery and diagnosis of PTMC in Tianjin Medical University Cancer Hospital.DNA was extracted,and polymerase chain reaction?PCR?technique was used to detect the BRAF gene status.To analyze the mutation rate of BRAF^V600E mutation in PTMC and the correlation with clinicopathological features such as gender,age of diagnosis,tumor size,multifocal,bilateralism and lymph node metastasis.In the third part,randomly selected 20 patients with PTC treated with thyroid surgery in Tianjin Medical University Cancer Hospital from October 2015 to February 2016.RNA was extracted,the m RNA expression of PKM2 and LDHA in thyroid carcinoma tissue and matched normal tissue were examined using real-time PCR.150 cases of paraffin-embedded tissues diagnosed as thyroid papillary carcinoma from May 2014 to December 2015 were collected from the Tianjin Medical University.Immunocytochemistry were used to examine the expression of PKM2 and LDHA in human thyroid tissues.Analysis PKM2 expression in PTC correlated with clinicopathological features.Results:1.The central lymph node metastasis rate of the 1587 PTMC patients was 30.9% and the lymph node metastasis rate was 4.6%.Univariate analysis showed that there was a significant difference between gender,age,tumor size,tumor location,multifocal,bilateralism,extrathyroidal extension,pathologic subtype and central lymph node metastasis?P<0.05?.Multivariate logistic regression analyses demonstrated that male gender,age ?45 years old,tumor diameter ?6 mm,extrathyroidal extension and bilateralism served as independent predictors for central lymph node metastasis?P<0.05?.For lateral lymph node metastasis,univariate analysis showed that the relationship between lateral lymph node metastasis and tumor size,extrathyroidal extension,multifocal,bilateralism,central lymph node metastasis were statistically different.Tumor diameter?8mm and central lymph node metastasis are independent risk factors for lateral lymph node metastasis.For patients with a solitary primary tumor,tumor location in the lower third of the thyroid lobe and isthmus was associated with a higher risk of CLNM?P<0.05?.And tumor location in the upper pole was associated with a higher risk of LLNM?P<0.05?.2.The incidence of BRAF^V600E mutation in PTMC patients was 63.2%.BRAF^V600E mutation is significantly associated with highrisk clinicopathologic characteristics.Compared with male patients,the mutation rate of BRAF^V600E is higher in females,the difference is statistically significant?P<0.05?.Compared to BRAF^V600E mutations in wild type patients,mutant PTMC patients have higher rate in CLNM and LLNM,the difference is statistically significant?P<0.05?.Multivariate analysis showed that BRAF^V600E mutation was an independent risk factor for lymph node metastasis?P<0.05?.3.The m RNA of PKM2 and LDHA was aberrantly overexpressed in PTC.PKM2 overexpression was associated with poor clinicopathological features including BRAF^V600E mutation and lymph node metastasis.Conclusion:1.A prophylactic neck dissection of the central compartment must be considered particularly in male PTMC patients with age <45 years,tumor size ?6 mm,extrathyroidal extension,and tumor bilaterality.2.PTMC patients with central lymph node metastasis and tumor diameter ?8 mm should pay close attention to lateral lymph node,if necessary,have lateral lymph node dissection.3.BRAF^V600E mutation of PTMCs presented higher rate of CLNM and LLNM,which shows that BRAF^V600E mutation may be related to the high aggressiveness of PTMC tumor.The treatment of lymph node in BRAF^V600E mutation should be in a more aggressive method.4.The expression of PKM2 and LDHA were increased in papillary thyroid carcinoma,and PKM2 overexpression was associated with BRAF^V600E mutation and lymph node metastasis.