Proteomic Comparison Based On PET/CT Defined Metabolic Tumor Volume In Non-metastatic Nasopharyngeal Carcinoma

PurposeTo lay the foundation for the studying of the development of molecular mechanisms and the seeking of therapeutic targets for nasopharyngeal carcinoma,isobaric tags for relative and absolute quantification（iTRAQ）technology is used and combined with nano-Reversed phase liquid chromatography-mass spectrometry（nano-RPLC-MS/MS）to analyze differentially expressed proteins in metabolic volume MTV of different primary tumors of nasopharyngeal carcinoma with SUV,and then marker protein molecules related to the size of primary tumors of nasopharyngeal carcinoma are found through the verification in nasopharyngeal carcinoma tissues by immunohistochemistry.MethodThe metabolic volumes MTV of primary tumors of totally 110 cases of retrospective data,including the data of the patient admitted to our hospital from January 2011 to December 2014 with nasopharyngeal carcinoma who is confirmed by pathology as having no distant metastasis and undergoing PET/CT examination before treatment,were separately calculated under SUV_2.5.According to the receiver operating characteristic（ROC）curve of 110 patients with nasopharyngeal carcinoma based on treatment failure events（relapse,metastasis,or death）,the best critical point was obtained.Twenty-five cases of nasopharyngeal carcinoma confirmed by pathology in FPCH were divided into two groups according to the threshold value of the optimal primary tumor volume.The proteins extracted from each group were labeled with iTRAQ reagent,and the differentially expressed proteins were identified by nanoRPLC MS/MS quantitative analysis.Differentially expressed proteins were analyzed by bio-informatics;With the paraffin tissues of 97 patients with nasopharyngeal carcinoma of the same period,immunohistochemistry was used to verify the expression of a certain marker protein in the metabolic volume of nasopharyngeal carcinoma based on PET/CT.Result1.Analyzed by ROC curve with nasopharyngeal cancer treatment failure（recurrence,metastasis,or death）as the endpoint,the ROC curve below the MTV（AUC）is 0.726.And the best cutoff point for MTV is 9.88 ml（approximately 10 ml）.It means the prediction of treatment failure of nasopharyngeal carcinoma has high sensitivity and specificity（0.750,0.723）.Furthermore,patients with nasopharyngeal carcinoma in MTV≤10 ml have higher disease-free survival rate compared with patients in MTV>10ml（93.5%vs 81.3%,P=0.035）.2.Twenty-five cases of nasopharyngeal carcinoma were divided into two groups with the best critical point of MTV（≤10ml or>10ml）for proteomics analysis.A total of 7913 proteins were identified,of which 360 significantly differently expressed.In MTV>10ml group,totally the expression of 244 proteins is up-regulated and of 116 is down-regulated.Under GO analysis and clustering,these proteins are mainly localized in organelles（34%）,cytoplasm（20%）,extracellular matrix（13%）,and plasma membrane structure（10%）,involved in cell growth,metabolic regulation,stimulation,differentiation and development,cell localization,immune response,substance transport,signal transduction,cell adhesion,cell movement and other biological processes,with nucleotide binding,structural molecular activity,protein binding,catalytic activity,small molecule binding and other molecules Features.Analysis of the KEGG signaling pathway suggests that these differential proteins are involved in signaling pathways associated with substance metabolism and some cellular migration and inflammation-related pathways.The PPI interaction network map of differentially expressed proteins in PET/CT-MTV nasopharyngeal carcinoma was constructed,whose result showed that the core proteins are mainly involved in protein phosphorylation,signal transduction,cell adhesion,cell growth,cell proliferation,apoptosis,cytoskeleton,cell movement,angiogenesis,and epithelial to mesenchymal transition.3.In 97 cases of nasopharyngeal carcinoma paraffin tissue samples,immunohistochemical analysis shows that the differential proteins TRIM29 screened by ITRAQ are closely related to the volume of nasopharyngeal carcinoma,that is,the asopharyngeal carcinoma tissue in the MTV>10ml group has higher TRIM29 protein expression than in the MTV≤10ml group（χ²=19.041,P<0.001）.Conclusion1.The optimal cut-off value for the metabolic volume of different primary tumors of nasopharyngeal carcinoma based on PET/CT,which is used to assess treatment failure of nasopharyngeal carcinoma,is 10ml through ROC curve.Patients with nasopharyngeal carcinoma with MTV≤10 ml have higher disease-free survival rate than patients with MTV>10 ml.2.Analyzed by iTRAQ technology and nanoRPLC-MS/MS,in MTV>10 ml group,the expression of totally 244 proteins is up-regulated and of totally116 is down-regulated.The differential proteins are closely related tzhouwu o tumor cell growth,migration,metabolism,and immunity.3.The expression of TRIM29 proteins are highly expressed in the MTV>10ml group and could be considered as marker proteins closely related to the primary tumor volume of nasopharyngeal carcinoma.