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Hirschberg et al. Neuroimmunol Neuroinflammation 2018;5:27 Neuroimmunology and
DOI: 10.20517/2347-8659.2018.31 Neuroinflammation

Review Open Access

Photodynamic therapy mediated immune therapy of
brain tumors

Henry Hirschberg , Kristian Berg , Qian Peng 3
2
1
1 Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA 92617, USA.
2 Department of Radiation Biology, Norwegian Radium Hospital, Oslo University Hospital, Montebello, Oslo N-0310, Norway.
3 Department of Pathology, Norwegian Radium Hospital, Oslo University Hospital, Montebello, Oslo N-0310, Norway.
Correspondence to: Prof. Henry Hirschberg, Beckman Laser Institute and Medical Clinic, University of California, Irvine 1002 Health
Sciences Rd, Irvine, CA 92617, USA. E-mail: hhirschb@uci.edu

How to cite this article: Hirschberg H, Berg K, Peng Q. Photodynamic therapy mediated immune therapy of brain tumors.
Neuroimmunol Neuroinflammation 2018;5:27. http://dx.doi.org/10.20517/2347-8659.2018.31

Received: 31 May 2018 First Decision: 7 Jun 2018 Revised: 14 Jun 2018 Accepted: 20 Jun 2018 Published: 10 Jul 2018
Science Editor: Athanassios P. Kyritsis Copy Editor: Jun-Yao Li Production Editor: Huan-Liang Wu

ABSTRACT
Photodynamic therapy of tumors requires the topical, systemic or oral administration of a photosensitizing
compound,illumination of the tumor area by light of a specific wavelength and the presence of oxygen. Light
activation of the photosensitizer transfers energy to molecular oxygen creating singlet oxygen, a highly reactive
and toxic species that rapidly reacts with cellular components causing oxidative damage, ultimately leading to cell
death. Tumor destruction caused by photodynamic therapy is not only a result of direct tumor cell toxicity via the
generation of reactive oxygen species but there is also an immunological and vascular component involved. The
immune response to photodynamic therapy has been demonstrated to significantly enhance its efficacy. Depending
on a number of factors, including type of photosensitizer, light dose and dose rate, photodynamic therapy has been
shown to induce cell death via apoptosis, necrosis, autophagy and in particular immunogenic cell death. It is the
purpose of this review to focus mainly on the role photodynamic therapy could play in the generation of specific
anti-tumor immunity and vaccines for the treatment of brain tumors.

Keywords: Photodynamic therapy, photochemical internalization, photodynamic therapy induced cell death, anti-
brain cancer vaccine

INTRODUCTION
Tumor resection is the primary treatment employed in the treatment of high grade gliomas (HGG). The
main functions of surgery are decompression of the brain, obtaining a histopathological and molecular

© The Author(s) 2018. Open Access This article is licensed under a Creative Commons Attribution 4.0
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