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Schulze et al. J Cancer Metastasis Treat 2020;6:42 I http://dx.doi.org/10.20517/2394-4722.2020.79 Page 7 of 10

CONCLUSION AND FUTURE DIRECTIONS
Due to their role in cancer progression and biological features, exosomes possess promising potential for
cancer therapy. To date, numerous exosomes-based cancer therapies have been studied and developed
including applying naturally derived immune cell exosomes to suppress cancer cells, inhibiting cancer
cells-derived exosomal activity, and using exosomes as gene/drug carriers. However, there are considerable
challenges to be solved. First, the difference among exosomes from different sources is still not clear.
Second, the exosome number to get a therapeutic effect may be significantly different among different
cancers. Third, scalability and heterogeneity of tumor may influence therapeutic outcome. Moreover,
different functions of exosomes derived from different sources are not fully studied. Furthermore,
knowledge on how exosomes can be modified so that they possess a high degree of specificity to particular
cancer cells remains unclear. Finally, the storage and the stability of exosomes remains ill-defined. With
these challenges, there is a vital need to systematically characterize exosomes derived from different cells/
tissue to choose the most efficient cells for specific cancer therapy. There is a further need to identify the
specific cancer cell surface markers for designing exosomes as drug carriers with high specificity to cancer
cells. Moreover, because of the complexity and the heterogeneity of the tumor, exosome-based cancer
may need to combine with other approaches. Finally, clinical trials of exosome-based cancer therapy are
urgently needed to determine the efficacy of the application. While there are still challenges ahead, it is
clear that exosomes offer novel and important applications for the treatment of cancer.

DECLARATIONS
Acknowledgments
All figures were created with BioRender.com.

Authors’ contributions
Conceived the general idea of the review, made up the structure and searched the literature: Deng F
Drafted the manuscript: Schulze AV, Deng F

Availability of data and materials
Not applicable.

Financial support and sponsorship
None.

Conflicts of interest
All authors declared that there are no conflicts of interest.

Ethical approval and consent to participate
Not applicable.

Consent for publication
Not applicable.

Copyright
© The Author(s) 2020.

REFERENCES
1. Carter S, Thurston DE. Immuno-oncology agents for cancer therapy. Pharmaceut J 2020; doi: 10.1211/PJ.2020.20207825.
2. Daßler-Plenker J, Küttner V, Egeblad M. Communication in tiny packages: exosomes as means of tumor-stroma communication. Biochim
Biophys Acta Rev Cancer 2020;1873:188340.