**9. Extracellular vesicles as biomarkers—new diagnostic tools**

In different body fluids, especially plasma and serum, EVs biomarkers have been detected with great clinical value in various types of cancer, **Table 2**.

The protein content of the EVs can be potentially used in the early detection of cancer as suggested in a pilot study by Smalley et al. [151]. The plasma levels of exosomal proteins represents an important biomarker that discriminates between ovarian cancer patients and normal ones, and their values correlate with the stage of the disease [119]. Among exosomal proteins, TGF-β1 and MAGE3/6 can be used as reliable biomarkers to discriminate between benign and malignant ovarian tumors, or to ascertain the efficacy of chemotherapy [119]. Although epithelial cell adhesion molecule (EpCAM) was demonstrated to promote epithelial-mesenchymal transition in advanced stages of endometrial cancer [152], studies indicated that EpCAM is not a robust biomarker to classify exosomes derived from benign and malignant ovarian tumors [134] or to detect early stages of the pathology [153]. Besides EpCAM, several exosomal proteins were identified to be overexpressed in ovarian cancer, including proliferation cell nuclear antigen (PCNA), tubulin beta-3 chain (TUBB3), epidermal growth factor receptor (EGFR), apolipoprotein E (APOE), claudin 3 (CLDN3), fatty acid synthase (FASN), ERBB2, and L1CAM (CD171) [127]. Additionally, claudin-4, but not claudin-3, is a valuable biomarker in the peripheral blood of ovarian cancer patients with almost 98% specificity [133]. Exosomal proteins can also represent important biomarkers for the evaluation of efficacy of therapies. Thus, annexin A3 can be employed for early detection of the resistance to platinum-based therapy in ovarian cancer patients [135, 136].

In breast cancer, several studies identified various exosomal miRNAs as potential biomarkers correlated with tumor malignancy degree and prognosis. Indeed, exosomal miR-21 and miR-1246 had higher levels in plasma of breast cancer


#### **Table 2.**

*Biomarkers contained in EVs relevant in different types of cancer.*

patients compared to control patients [138]. Additionally, high levels of exosomal miR-939 were associated with low outcome in patients with triple-negative breast cancer [139], and high levels of exosomal miR-373 were identified in triplenegative, estrogen–receptor- and progesterone-receptor-negative, breast cancer patients [58]. Moreover, an extensive proteomics analysis identified alpha1 antitrypsin and haptoglobin precursors as novel biomarkers in the serum of patients with infiltrating ductal breast carcinomas [137].

The release of EVs has a calcium-dependent mechanism, and alterations in calcium signaling have been described in tumorigenesis, metastasis, or drug resistance in various types of cancer, including breast and ovarian cancers [154, 155]. Therefore, more attention should be paid to the calcium-dependent signaling cascades in different cancer stages in direct relationship with the cell-to-cell communication mechanisms of EVs in order to identify novel specific and reliable biomarkers.

### **10. Therapeutic roles of extracellular vesicles in cancer**

EVs have a big potential for cancer therapy monitoring (**Table 3**). These are described as secreted lipid bilayer-enclosed lumens and are claimed to be valuable reservoirs of liquid biopsy biomarker [156]. EVs (mainly EVs-associated proteins and microRNAs) are proved to be the biomarkers in breast cancer diagnosis [157, 158].

**99**

*Extracellular Vesicles in Cancer*

Tumor peptide-loaded dendritic cells-derived exosomes

EVs from the rat pancreatic adenocarcinoma cell line BSp73ASML

leukemia cell line)

stimulating factor

endothelial cell line

cells

EVs

**Table 3.**

**11. Integrative overview**

EVs play an essential role in cellular communication both in physiological and pathological conditions. In pathological conditions, EVs have been implicated in cancer, spreading of viruses or other pathogens, altered immune response, development of neurodegenerative diseases, etc. In cancer, EVs ensure the cross talk between tumoral cells or between tumoral cells and nontumoral cells, and enable the development of multiple processes, including tumorigenesis, pre-metastatic niche formation, metastasis, and drug resistance. In ovarian and breast cancers, the involvement of EVs in all these processes of tumor evolution has been described and the analysis of EVs content is particularly useful for identifying biomarkers of the disease per se and, moreover, for the stage of the pathology evolution. However, there are still technical limitations for separation and/or analysis of EVs, and in clinical practice, the standardization of EVs-based reproductible protocols is required urgently. Considering the presence of EVs in such a variety of body fluids and tissues, an important conclusion is to consider EVs both as biomarkers and potential therapeutic targets (especially for immunotherapies) and to exploit them

**Source of EVs Therapeutic effect Reference**

tumor growth

Tumor antigen containing EVs Activates an antitumor response against

EVs from self-derived dendritic cells Immunotherapy in cases of unresectable

cells

model

iRGD-Exos-doxorubicin Suppressed breast tumor growth in an

Immunotherapy—because they suppress

OVA-transfected BL6–10 melanoma cells

Activates CTLs through self-derived

dendritic cell activation

nonsmall-cell lung cancer

Adjuvant therapy in immunotherapy [160]

Metastatic melanoma patients [163]

Immunotherapy in colorectal cancer [164]

Chemosensitive in glioblastoma multiforme

MDA-MB-231 tumor-bearing nude mouse

Treating endothelial cell dysfunction during

hyperhomocysteinemia in vitro

[159]

[160]

[161]

[162]

[165]

[166]

[167]

in the next future to improve the outcome of cancer patients.

*DOI: http://dx.doi.org/10.5772/intechopen.85117*

EV vaccine derived from colorectal cancer (NB4 cell—a human acute promyelocytic

EVs from autologous self-derived dendritic

EVs from ascites in combination with granulocyte macrophage colony-

miR-9 in mesenchymal stem cell-derived

Curcumin-primed EVs from a mouse brain

*EVs and their role in therapeutic approaches in cancer.*


**Table 3.**

*Extracellular Vesicles and Their Importance in Human Health*

TGF-beta1, MAGE3/6, and

Alpha-1-antitrypsin and haptoglobin precursors

miR-1290 and miR-375 Survivin, CD9+, CD63+, and alpha-1-antitrypsin

miR-21, miR-939, miR-373, and

miR-1246, miR-4644, miR-3976,

CD44v6, Tspan8, EpCAM, and

Alpha-1-antitrypsin, and histone

Claudin-4

miR-1246

and miR-4306

CD104

H2B1K

**Table 2.**

patients compared to control patients [138]. Additionally, high levels of exosomal miR-939 were associated with low outcome in patients with triple-negative breast cancer [139], and high levels of exosomal miR-373 were identified in triplenegative, estrogen–receptor- and progesterone-receptor-negative, breast cancer patients [58]. Moreover, an extensive proteomics analysis identified alpha1-

miR-21 Plasma Esophageal cancer [149] miR-19a l Serum Colorectal cancer [150]

**Biomarkers of EVs Sample Types of cancer Reference**

EpCAM and annexin A3 Serum [134–136]

IL-8 and TGF-beta mRNAs Plasma Glioma [60] miR-21 CSF [145]

long coding RNA CRNDE-h Serum Lymph node and distant metastasis of

Plasma Ovarian cancer [119, 133]

Serum Breast cancer [137]

Plasma [58, 138, 139]

Plasma Prostate cancer [140–144]

Serum Pancreatic cancer [146]

Urine Urothelial carcinoma [147]

[148]

colorectal cancer

antitrypsin and haptoglobin precursors as novel biomarkers in the serum of patients

EVs have a big potential for cancer therapy monitoring (**Table 3**). These are described as secreted lipid bilayer-enclosed lumens and are claimed to be valuable reservoirs of liquid biopsy biomarker [156]. EVs (mainly EVs-associated proteins and microRNAs) are proved to be the biomarkers in breast cancer

The release of EVs has a calcium-dependent mechanism, and alterations in calcium signaling have been described in tumorigenesis, metastasis, or drug resistance in various types of cancer, including breast and ovarian cancers [154, 155]. Therefore, more attention should be paid to the calcium-dependent signaling cascades in different cancer stages in direct relationship with the cell-to-cell communication mechanisms of EVs in order to identify novel specific and reliable

with infiltrating ductal breast carcinomas [137].

*Biomarkers contained in EVs relevant in different types of cancer.*

**10. Therapeutic roles of extracellular vesicles in cancer**

**98**

biomarkers.

diagnosis [157, 158].

*EVs and their role in therapeutic approaches in cancer.*
