Proteomics can analyze and identify the changes of protein molecules in tumor cells, providing valuable information for the diagnosis of tumors. At present, many researchers used proteomics technology has been in oral squamous carcinoma, prostate cancer, liver cancer, breast cancer, colorectal cancer, ovarian cancer, bladder cancer, renal cell carcinoma, and has obtained certain achievements in the research of lung cancer and so on and some tumor proteome database has been established, many tumor markers and some tumor-associated protein have quietly come out.
Proteomic techniques: discovery proteomics, comparative proteomics, modified proteomics, targeted proteomics, polypeptide proteomics.
Application in oral squamous cell carcinoma
Ral SquC cell carcinoma(OSCC) is the most common type of cervical malignancy with high prevalence and incidence. OSCC has specific histological and molecular characteristics that are different from tissue regions. With the limitation of clinical staging based on the tumor-nod-metastasis (TNM) marker, the recurrence rate of OSCC in patients receiving standard care ranged from 18% to 76%. Therefore, biomarkers to evaluate the outcome of OSCC patients have important clinical significance.
Application in hepatocellular carcinoma
Hepatocellular carcinoma (HCC) is one of the most common malignancies, ranking sixth in morbidity and third in mortality worldwide. The high frequency of early metastasis means that HCC is usually diagnosed at an advanced stage, reducing the likelihood of a timely cure. Therefore, it is very important to diagnose early HCC by detection such as serum biomarkers. ITRAQ proteomic techniques were used to screen for differentially expressed proteins in hepatitis B (HBV, n=10), liver cirrhosis (LC, n=10), hepatocellular carcinoma (HCC, n=10) and healthy controls (HC, n=10). In addition, k-means cluster analysis, GO and series network analysis were performed for potential HCC markers, and finally three HCC markers (CD14/GELS/QSOX1) were selected. WB verification was performed, and after comprehensive analysis, CD14 molecule was locked and confirmed by ELISA assay, and it was found that it has the potential as a diagnostic marker for early liver cancer.
Application in the study of cholangiocarcinoma
Cholangiocarcinoma (CCA) includes a group of heterogeneous cholangiocarcinomas with poor prognosis. Certain conditions are risk factors, such as primary/sclerosing/cholangitis (PSC). Non-invasive differential diagnosis between intrahepatic CCA and hepatocellular carcinoma (HCC) is sometimes difficult. Ander Arbelaiz and his team selected serum samples from 43 cases of cholangiocarcinoma, 30 cases of cholangitis, 29 cases of hepatocellular carcinoma and 32 cases of normal controls, and identified differentexpression proteins in exosome samples by proteomic analysis. The expression of FIBG, IGHA1, VNN1, CRP, GGT1andA1AG1, and GGT1andA1AG1 were significantly higher in cholangiocarcinoma than in the other three samples, with CRP protein showing a higher diagnostic value. Later, after xenotransplantation of CCA, the authors identified 23 human proteins from the proteomic analysis of mouse blood exosomes, demonstrating that tumor exosomes can be secreted into the blood. It is suggested that CRP protein and other novel marker proteins found in serum EV have potential application value as diagnostic tools.
Application in lung cancer research
Lung cancer is a cancer with a very high mortality rate, with a survival rate of 15 percent, the lowest of all cancers. A total of 51 differentially expressed proteins were identified in Grasso CS by iTRAQ and mass spectrometry, of which 29 proteins were up-regulated and 22 proteins were down-regulated. The down-regulated proteins are mainly enzymes involved in regulating nutrition or drug metabolism. And most of the proteins (tropomyosin/HEAT shock protein 27/ transglutaminase…) induced by TGF-β It is involved in the regulation of cell migration, adhesion and invasion, and plays a certain role in the occurrence and development of cancer.
 J Guo, R Jing, et al. Identification of CD14 as a potential biomarker of hepatocellular carcinoma using iTRAQ quantitative proteomics[J]. Oncotarget.
 Ander Arbelaiz, et al. Serum extracellular vesicles contain protein biomarkers for primary sclerosing cholangitis and cholangiocarcinoma[J]. Hepatology.
 Grasso C S . Differential protein expression profiling by iTRAQ-2DLC-MS/MS of lung cancer cells undergoing epithelial-mesenchymal transition reveals a migratory/invasive phenotype[J]. Journal of Proteome Research.