Screnning And Evaluation For Novel Biomarkers Of Lung Cancer Based On Low-abundance Proteome

Lung cancer is the disease with the highest morbidity and mortality among various malignancies wordsild.Non-small cell lung cancer(NSCLC)is the main type of lung cancer,accounting for about 85%of lung cancer patients.NSCLC has strong individal difference and heterogeneity,high malignancy,and poor prognosis.It is difficult to meet clinical needs through traditional and conventional diagnostic methods,and it is invasive,time-consuming,expensive,and poor in patients compliance,so there is a need for diagnostic method that is sample and fast to use,minimally invasive or noninvasive,convenient to sample and highly accurate.Plasma contains a large number of comprehensive types of proteins in human body,which can accurately reflect the physical condition.In addition,compared to traditional diagnostic methods,it is very convenient to obtain biological samples,and it can be sampled multiple times at regular intervals to dynamically and comprehensively predict disease changes in time and space,so plasam is more suitable for mining biomarkers.Purpose: screening low-abundance differentially expressed proteins in plasma of NSCLC,mining NSCLC biomarkers with potencial diagnosis value,assessing the potencial value of biomarkers.Methods: collect plasma form NSCLC patients and heathy people,remove high-abundance proteins for comparative proteomics analysis,and screen out all differentially expressed proteins(P < 0.05,Fold change value > 1.2).Bioinformatics analysis of all differentially expressed proteins,including protein annotation,protein function enrichment and protein interaction network constrution,to screen out potentially valuable proteins.At the same time,several proteins with diagnostic value were selected by reading literature,these proteins was verified by ELISA experiments,and tissue expression levels were dectected by immunohistochemistry.Results: A total of 1,237 proteins were identified by proteomics,and 1058 of them were relatively quantified.Finally,173 differentially expressed proteins were screened,of which 73 were up-regulated and 100 were down-regulated.According to the enrichment results of the KEGG pathway,it was found that differentially expressed proteins were significantly enriched in the complement system and the coagulation cascade signaling pathway,including two proteins,CFH and C9.ELISA test results of CFH,C9 and other proteins(C4d,C5 a,SAA2,AAT and IDH1)showed that compared with the healthy group,the expression levels of C9,C4 d,SAA2 and AAT in the lung cancer group were significantly increased,which was statistically significant(P < 0.05),C9,C4 d,C5a,SAA2 and AAT were significantly up-regulated in the benign control group,which was statistically significant(P < 0.05).Compared with the benign control group,the expression levels of C4 d and SAA2 in the lung cancer group were significantly increased,which was statistically significant(P < 0.05).Among them,SAA2 can completely identify patients with lung cancer,and immunohistochemical results show that SAA2 is also significantly up-regulated in tissues.Conclusion: From our lung cancer plasma protein profiling screen to the marker C9 protein,experimentally verified that the expression levels of C9,C4 d,SAA2 and AAT were significantly up-regulated,indicating that these four proteins have potential as diagnostic markers for non-small cell lung cancer,and have promising applications It provides a new method for the diagnosis of non-small cell lung cancer in clinic.