Clinical Study Of ITRAQ-based Proteomics For Screening And Validating Serum Markers Of Pancreatic Cancer

Objective To identify and verify serum biomarkers for early diagnosis of pancreatic cancer,so as to improve early diagnosis rate and prognosis of pancreatic cancer patients.Methods(1)iTRAQ(isotope labeling relative and absolute quantitative technique)combined with LC-MS/MS(liquid phase-mass spectrometry/mass spectrometry)was used to determine the differentially expressed proteins in serum of patients with pancreatic cancer and healthy people,and bioinformatics analysis was performed.(2)ELIS As(enzyme-linked immunosorbent assays)were applied to determine the levels of differentially expressed proteins and CA19-9(carbohydrate antigen 19-9)in the serum.ROCs(the receiver-operating characteristic curve)were used to compare the efficiency of differentially expressed proteins and CA19-9 in the diagnosis of pancreatic cancer.Proteins whose efficiency were better than that of CA19-9 were selected for further researches,as well as CA19-9.(3)ELISAs were used for determination of the expression levels of selected proteins and CA19-9 in the serum.ROCs were used for the evaluation of efficiencies for early diagnosis of pancreatic cancer of the proteins separately or jointly.NRI(net classification index)was performed to compare the efficacy of protein panel and CA19-9 in early diagnosis of pancreatic cancer.Results(1)A total of 869 proteins were identified,among which 55 were differentially expressed in the serum of pancreatic cancer patients and healthy people,18 were highly expressed in the serum of pancreatic cancer patients,and 37 were poorly expressed.(2)The levels of PROZ(vitamin k-dependent protein Z),TNFRSF6B(tumor necrosis factor receptor superfamily member 6B)and CA19-9 in the serum of pancreatic cancer were significantly higher than those in healthy people and pancreatic benign tumors with statistical significance(P<0.01).In their ROCs,the AUCs of PROZ and TNFRSF6B were higher than that of CA19-9 with statistical significance(P<0.05).The AUC of PROZ combined with TNFRSF6B was higher than that of TNFRSF6B alone with statistical significance(P=0.0026).(3)The AUCs of ROCs of the panel combining PROZ,TNFRSF6B and CA19-9 in discriminating stage I pancreatic cancer patients from pancreatic benign tumor patients and healthy people were higher than those of PROZ,TNFRSF6B,CA19-9 when used separately(P<0.05).(4)Comparing the efficacies of the panel of PROZ,TNFRSF6B and CA19-9 and CA19-9 alone n discriminating stage I pancreatic cancer patients from pancreatic benign tumor patients and healthy people,the additive NRI is 27.0 and the absolute NRI was 13.0%.Conclusion PROZ and TNFRSF6B are novel serum biomarkers for the detection of pancreatic cancer,and the panel of PROZ,TNFRSF6B and CA19-9 can distinguish early pancreatic cancer from pancreatic benign tumors and healthy individuals.