Exosome as potential biomarkers for gastrointestinal tumors

Exosomes are polyvesicles that are formed by invagination of intracellular lysosomal particles, and are released into the extracellular matrix after the fusion of polyvesicular outer membrane and cell membrane. In the body, immune response, antigen presentation, cell migration, cell differentiation and tumor invasion are closely related to tumorigenesis and tumor progression. This study aimed to conduct a meta-analysis for evaluating the clinicopathological, diagnostic and prognostic significance of exosomal expression in gastrointestinal tumors.

The original English articles were systematically searched in the online databases. The diagnostic accuracy, prognostic utility and clinicopathological correlation of gastrointestinal tumors were investigated. The quality assessment for studies of diagnostic accuracy II and Newcastle-Ottawa scale were used for quality evaluation, and the data was strictly extracted to judge the deviation of the study.

A total of 14 studies with 1837 gastrointestinal tumor patients were included. The change in exosomal expression showed significant correlation with poor clinicopathological parameters (tumor diameter: combined P = .00024394; differentiation: combined P = 2.796e-08; lymphatic metastasis: P = 9.610e-07; distant metastasis: combined P = .00017326; pathological classification: combined P = .00875213; invasion depth: combined P = 3.504e-08) carcinoembryonic antigen (combined P = . 04458857) and tumor location (combined P = .00145983). The difference in the area under the curve between gastrointestinal tumor patients and healthy people showed an area under the curve of 0.89 (95%Cl 0.85-0.91) and heterogeneity of 0.59, 95% CI=[0.55-0.68]. The sensitivity was 0.88 (95%Cl 0.83 mi 0.91), the specificity was 0.72 (95%Cl 0.63 mi 0.80), and the diagnostic odds ratio was 18 (10-33). The results of survival analysis revealed that the abnormally expressed exosomes were significantly correlated with poor overall survival (hazard ratio =2.81, 95% CI: 2.02-3.93, P=0.013∗ 62.7%∗).

The abnormally expressed exosomes might act as auxiliary biomarkers in diagnosing gastrointestinal tumors and demonstrated good prognostic significance in predicting the survival of patients with gastrointestinal tumors.