Theranostics 2022; 12(10):4734-4752. doi:10.7150/thno.69682 This issue


Challenges and opportunities to penetrate the blood-brain barrier for brain cancer therapy

Dannielle H. Upton1,2*, Caitlin Ung1*, Sandra M. George1, Maria Tsoli1,2, Maria Kavallaris1,2,3, David S. Ziegler1,2,4✉

1. Children's Cancer Institute, Lowy Cancer Research Centre, UNSW Sydney, Sydney, NSW, 2031, Australia.
2. School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, 2052, Australia.
3. Australian Centre for Nanomedicine, UNSW Sydney, Sydney, NSW 2052, Australia.
4. Kids Cancer Centre, Sydney Children's Hospital, Randwick, NSW 2031, Australia.
*Equal authorship.

This is an open access article distributed under the terms of the Creative Commons Attribution License ( See for full terms and conditions.
Upton DH, Ung C, George SM, Tsoli M, Kavallaris M, Ziegler DS. Challenges and opportunities to penetrate the blood-brain barrier for brain cancer therapy. Theranostics 2022; 12(10):4734-4752. doi:10.7150/thno.69682. Available from

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Graphic abstract

Despite significant advances in research, the prognosis for both primary and secondary brain cancers remains poor. The blood-brain barrier (BBB) is a complex and unique semi-permeable membrane that serves as a protective structure to maintain homeostasis within the brain. However, it presents a significant challenge for the delivery of therapeutics into the brain and tumor. Some brain tumors are known to compromise BBB integrity, producing a highly heterogeneous vasculature known as the blood-tumor-barrier (BTB). Identifying strategies to bypass these obstacles to improve the penetrability of anticancer therapeutics has been the focus of research in this area. In this review, we discuss the strategies that have been investigated to evade or alter the cellular and molecular barriers of both the BBB and the BTB and detail the methods currently under preclinical or clinical investigation, including molecular, biological, and physical processes to overcome the BBB or BTB. Increased understanding of the BBB and BTB and the current methods of overcoming these barriers will enable the development of new and more effective treatment strategies for brain tumors.

Keywords: brain tumors, CNS malignancies, blood brain barrier, drug delivery systems, BBB disruption