The Role Of Bsrtc Grading And BRAF^V600Emutation Analysis Using FNA Samples On Preoperative Diagnosis Of Papillary Thyroid Carcinoma And Proteomics Analysis Of Papillary Thyroid Carcinoma

Objective:Thyroid cancer ranks as the most common malignant endocrine tumor.Papillary thyroid carcinoma（PTC）accounts for about 90%of thyroid cancer cases,and is always the most popular pathological type.Main manifestation of PTC patients is thyroid nodules,while as much as19%～68%of the total population can be diagnosed as thyroid nodules using ultrasound.However,among those patients,only 7%～15%are finally diagnosed as thyroid cancer.Currently TI-RADS and ultrasound-guided fine needle aspiration（FNA）have been widely implemented in hundreds of Chinese hospitals,which are designed to improve the diagnostic accuracy of thyroid nodules.However,even though we have developed the detect approaches mentioned above,about 10%～40%patients are still“undiagnostic patients”.In the past,those patients have to receive diagnostic lobectomy ultimately,which also represents great number of unnecessary surgeries,and lots of avoidable costs or complications.Many guidelines recommend performing molecular diagnosis based on FNA samples.Till now,there is no relevant data on molecular diagnosis of a large population size in China.Additionally,PTC easily metastasis to surrounding lymph nodes,and a comprehensive pre-operative evaluation of lymph node metastasis status is essential to both patients and surgeons in terms of refining treatment plan,lowering the risk of recurrence and secondary surgery.We carried out BRAF mutation examination using FNA samples and screening differential expressed proteins by mass spectrometry using tissue samples,and hope to refine the diagnosis and treatment process of patients with thyroid nodules and PTC.Methods:We constitutively recruited 2307 patients who received FNA examination in Shanghai Jiaotong University School of Medicine affiliated Renji Hospital during April 2016 to October 2018.Results of FNA including pathological diagnosis by the Bethesda System for Reporting Thyroid Cytopathology（BSRTC）system and BRAF^V600Emutation status.We analyzed the relationship of BSRTC and BRAF^V600Emutate status,and of clinicaopathological features of patients with PTC and BRAF^V600E mutation usingχ2 test.We then calculated predictive efficiency of three predicting models,namely BSRTC（B model）,BRAF^V600E（M model）and combining model（BM model）on pre-operative diagnosis of PTC.Next,we performed HPLC-MS examination on 30 tissue samples:benign thyroid tumor（n=10）,PTC with（n=10）or without（n=10）lateral neck lymph node metastasis.The proteomics results are identified through Maxquant and Swiss Prot database,and the differential expressed proteins,GO enrichment and KEGG pathway enrichment are analyzed through R studio.Results:BRAF^V600E mutation rate increases as the BSRTC grading goes up in FNA population（P=0.000）.BRAF^V600E mutation is positively related to multifocality in papillary thyroid microcarcinoma（PTMC）（P=0.007）,while no significant correlation is notice between age,gender,central lymph node metastasis（CLNM）,lateral lymph node metastasis（LLNM）and BRAF^V600E mutation（P>0.05）.BM combined model serve as the optimal predicting model,with a top AUC of 0.889（P<0.05）.HPLC-MS shows great capability on differentiating three groups.Significantly higher levels of 294 proteins,including DPP4,CTSB and PC are noticed in PTC samples compare to benign tumor sample（FC>1.5,P<0.05）.GO enrichment analysis indicates an obvious activation of lysosome system,and KEGG pathway enrichment analysis demonstrate activated t RNA-acylation process as well as lysosome function.Conclusion:BRAF^V600E mutation examination is capable of improving the accuracy pf pre-operative diagnosis of PTC by FNA.BRAF^V600E mutation has no impact on CLNM rate of PTC patients,which indicates that prophylactic central lymph node dissection should be carried out without considering the BRAF^V600E mutation status.PTC is triggered by several mechanisms,including lysosome dysfunction,intracellular vacuole traffic,protein modification.There os significant difference between benign thyroid nodules and PTC,such as DPP4,CTSB and PC.We hope to provide more evidence on a more comprehensive and individualized approach to make pre-operative diagnosis and surgery plan.We also expect further exploration into basic researches into pathogenesis of PTC and lymph node metastasis.