## 4 Studies of the Molecular Profiling of EVs as Potential Biomarkers
### Proteome Profiling Analysis of EVs in Multiple Cancers
In addition, CK19, TAG72, and CA125 proteins were significantly enriched in EVs derived from CRC cells, tumor interstitial fluid, and patients' plasma [92] (Table 1). CA125 is an antigenic membrane protein of unknown function, however, the release of soluble proteolytic fragments of CA125 into the extracellular space appear to be associated with the conversion from benign to cancer cells [117]. In addition, CA125 together with HE4 are candidate biomarkers for ovarian cancer. So far, the serum EV CA125 and HE4 levels can significantly identify ovarian cancer at the early stage from healthy subjects, benign ovarian disease patients, and other gastrointestinal cancer patients [93; 94]. In regard to CRC, protein profiling studies of individual EVs led to the identification of CD147-positive EVs with high predictive value [95] (Table 1). CD147 is a glycoprotein \begin{table}
\begin{tabular}{c c c c} \hline
**Cancer Type** & **Biomarker** & **Sample** & **Authors** \\ \hline Prostate Cancer & FABP5, Granulin, AMBP, CHMP4A, and CHMP4C & urine derived-EVs & [103] \\ Bladder Cancer & MUC1, CEA, EPS8L2 and moesin & urine derived-EVs & [104] \\ Lung Cancer & MUC1 & plasma derived-EVs & [105] \\ Lung Cancer & NY-ESO-1, EGFR, PLAP and EpCam & plasma derived-EVs & [106] \\ Lung Cancer & LBP & serum derived-EVs & [107] \\ Lung Cancer & BPIFA1, CRNN, MUC5B, and IQGAP1 & saliva derived-EVs & [108] \\ Lung Cancer & LRG1 & urine derived-EVs & [109] \\ Glioblastoma & annexin A2, vimentin, tenascin-C and others & _In vitro_: A172, Glia-Tr, Glia-L, Glia-R, and Glia-Sh cell lines & [110] \\ Osophageal squamous cell & & _In vitro_: HEEPiC, Het-1A, TE-1, TE-5, TE-6, & \\ carcinoma & GPC1 & TE-8, TE-9, TE-10, TE-11, TE-14 and TE-15 & [111] \\ Nasopharyngeal & and LX-2 cell lines & _In vitro_: C666-1, NP69 and NP460 cell lines & [112] \\ carcinoma & ICAM-1, CD44v5 and TSP-1 & _In vitro_: C666-1, NP69 and NP460 cell lines & [112] \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._released by tumor cells in a soluble form, or by EVs involved in progression, invasion, and metastasis, suggesting it as a relevant tumor biomarker for cancer diagnosis [118]. Despite the advances in colon cancer (CC) diagnosis, clinical outcomes and survival rate remain poor. Studies on EVs derived from HCT-116 and HT-29 CC cells and plasma from CC patients showed high levels of tetraspanin 1 (TSPAN1) [96] (Table 1). TSPAN 1 is a member of the tetraspanin family, which may be involved in cancer progression (e.g., proliferation, cell migration, and motility) [96]. Moreover, annexins were increased in EVs derived from plasma of CC patients compared to those from healthy controls (HCs), showing a sensitivity of 75.7% [97] (Table 1). Annexin 2A (ANXA2) is a calcium-binding cytoskeletal protein expressed on the surface of endothelial cells, macrophages, mononuclear cells, and various types of cancer cells [119]. Elevated ANXA2 expression correlates with cell migration and invasion [120]. Furthermore, high-performance analysis has identified differential proteomic profiles in EVs from the serum of intrahepatic carcinoma (iCCA), hepatocellular carcinoma (HCC), and primary sclerosing cholangitis (PSC) patients versus control donors. Reports demonstrated that aminopeptidase N (AMPN, also known as CD13), pantetheinase (VNN1), and polymeric immunoglobulin receptor (plgR) showed good diagnostic capacity of CCA [98]. AMPN, ficolin-1 (FCN1), and neprilysin (NEP) showed good correlation with PSC compared to the healthy control group [98] (Table 1). VNN1 pantetheinase is a protein anchored to glycosylphosphatidylinositol (GPI) on the cell membrane, which participates in the synthetic pathway of pantothenic acid (vitamin B5), acting as a key regulator of tissue tolerance to stress in various diseases [121]. plgR seems to be involved in the promotion of cell transformation and proliferation, providing new insights into the role of immunoglobulin receptors [122].