Table 1: Summary of some studies in which tumor EVs have been assessed for their potential clinical use in disease monitoring and diagnosis of cancer patients.

Cancer typeEvidences reported in the paperReference

Ovarian cancer32 of 63 plasma samples from ovarian cancer patients contained exosomes containing claudin-4, a protein that is frequently overexpressed in ovarian cancers. Only 1 of 50 samples from control patients, instead, contained claudin-4-positive exosomes. The assay of exosomes-associated claudin-4 in blood could be useful, alone or in combination with other screening methods, for the detection of ovarian cancer.[103]

Ovarian cancerExosomes purified from plasma of patients with ovarian cancer carried cancer-specific miRNAs; women with early or advanced cancer showed similar miRNAs profiles, whereas healthy women or patients with benign ovarian disease expressed very different profiles. Thus, miRNA profiles of circulating exosomes could be used as diagnostic marker.[104]

GlioblastomaMutant mRNAs and miRNAs specific for gliomas can be detected in microvesicles from serum of glioblastoma patients. In 7 of 25 samples, for example, EGFRvIII was detected (the tumor-specific mutant splice variant of EGFR mRNA typical of many gliomas), but it was not found in serum exosomes from 30 control patients. Moreover, levels of miRNA-21, usually overexpressed in glioblastoma tumors, were higher in serum microvesicles from glioblastoma patients than in control patients. So, tumor-derived microvesicles could be used to obtain diagnostic information.[49]

Bladder cancerThis pilot study showed that microvesicles from urine of cancer patients contained 8 proteins whose levels were elevated, suggesting that protein composition of microvesicles could be used in early detection of bladder cancer.[105]

Gastric cancerPlatelet microparticles plasma levels were assessed in patient with gastric cancer. Levels were significantly higher in the patients than in the healthy controls and higher in patients with stage IV disease than those in patients with lower stages (I/II/III). Plasma levels of platelet microparticles had a high diagnostic accuracy and might be useful to identify metastatic gastric patients.[106]

Mucinous adenocarcinomasMicroparticles from blood of patients with breast and pancreatic cancer had significantly increased levels of tissue factor (TF) compared with healthy controls. Patients with higher levels of TF and MUC1 (epithelial mucin) in MVs were associated with a lower survival rate at 3–9 month followup compared to those with low TF-activity and no MUC1 expression, suggesting the possible use of plasma vesicles in prognosis of disease.[107]

Hormone refractory prostate cancerIn patients with hormone-refractory prostate cancer, platelet MVs levels were predictive of outcome; overall survival was significantly shorter in those patients with MVs level above the cut-off compared to those patients whose level was below it.[108]