Exosomes are secreted by cells and are widely present in body fluids. Exosomes contain various molecular constituents of their cells of origin such as proteins, mRNA, miRNAs, DNA, lipid and glycans which are very similar as the content in tumor cells. These contents play an important role in various stages of tumor development, and make the tumor-derived exosome as a hot and emerging biomarker for various cancers diagnosis and management in non-invasive manner. The present problems of exosome isolation and detection hinder the application of exosomes. With the development of exosome isolation and detection technology, the contents of exosomes can be exploited for early cancer diagnosis. This review summarizes the recent progress on exosomeassociated tumor biomarkers and some new technologies for exosome isolation and detection. Furthermore, we have also discussed the future development direction in exosome analysis methods. Development on exosome tumor markers Extracellular vesicle (EV) includes exosomes, microvesicles and apoptotic bodies. These vesicles have different size and biogenesis. Exosomes are complex 20-100 nm vesicles and generate in a way that intracellular multivesicular bodies (MVBs) containing intraluminal vesicles (ILVs) fuse with the plasma membrane [1]. Larger vesicles, microvesicles (100 nm-1 μm) and apoptotic bodies (1-5 μm), are released directly from the budding and fission of the plasma membrane [2]. In the past decades, researchers have become increasingly interested in the role of EVs, especially exosomes, in diseases. Exosomes contain various molecular constituents of their cell of origin such as proteins, RNAs, DNA, lipid glycans. Therefore, tumor-derived exosomes could tell the physiological and pathological states of parent tumor cells, and emerged to be a hot cancer biomarker in liquid biopsy field [3]. Given the rich molecular composition of exosomes and easy availability of liquid biopsy sample, many researchers [4] are pursuing to develop non-invasive diagnostic methods with higher sensitivity and specificity based on exosome, which has very high potential to help early diagnosis, treatment evaluation, and prognostic analysis of the disease. In this section, we have summarized the application of exosomes in tumor diagnosis based on its amount and molecular compositions. Level of exosomes in tumor diagnosis Studies show that the level of exosomes in plasma was significantly higher in cancers (such as ovarian cancer [5] and non-small-cell-lung cancer [6]) patients than that of healthy controls [7]. Therefore, many researchers hypothesize that levels of exosome in bodily fluid can serve as a potential diagnostic biomarker in cancer patients. Logozzi et al. [8] investigated the amount of

Golgi protein 73 (GP73, also referred to as Golph 2) with 400 amino acids is a 73 kDa transmembrane glycoprotein typically found in the cis-Golg complex. It is primarily expressed in epithelial cells, which has been found upregulated in hepatocytes in patients suffering from both viral and non-viral liver diseases. GP73 has drawn increasing attention for its potential application in the diagnosis of liver diseases such as hepatitis, liver cirrhosis and liver cancer. Herein, we reviewed the discovery history of GP73 and summarized studies by many groups around the world, aiming at understanding its structure, expression, function, detection methods and the relationship between GP73 and liver diseases in various settings.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Objectives: Tumour-targeted gene therapy is a promising approach for effective control of gastric cancer cell proliferation. Our study aims to develop a cancer therapy which combines tumour-targeting promoters with cytotoxins. Methods:The expression of globotriaosylceramide (Gb3), which is a Shiga-like toxin I (Stx1) receptor, was verified in gastric cancer compared with normal stomach tissues as assessed by flow cytometry and immunohistochemical analysis. We therefore constructed the recombinant pFZD7-Stx1 plasmid vectors with tumour-preferential Frizzled-7 promoter and Stx1. pFZD7-Stx1 was used to treat gastric cancer in vitro and in vivo. The gastric cancer cell proliferation and tumour growth were identified after the transfection with the pFZD7-Stx1.Results: Globotriaosylceramide was obviously increased in gastric cancer compared with normal stomach. The gastric cancer cell proliferation and tumour growth decreased significantly after the transfection with the pFZD7-Stx1.Conclusion: Frizzled-7 promoter is preferentially active, and Gb3 is abundant in gastric cancer cells. Frizzled-7 promoter and Stx1 may be used to determine a novel and relatively specific and potent gastric cancer therapeutic strategy.Taken together, the Frizzled-7 promoter is preferentially active and Gb3 is abundant in gastric cancer cells. An improved and comprehensive understanding of these and future methods that combine use of the Frizzled-7 promoter and Stx1 will define possibly definitive inhibiting of gastric cancer cell proliferation.

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