Combination immunotherapy and photodynamic therapy for cancer

Michael R. Hamblin, Ana P. Castano, Pawel Mroz

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)


Cancer is a leading cause of death among modern people largely due to metastatic disease. The ideal cancer treatment should target both the primary tumor and the metastases with minimal toxicity towards normal tissue. This is best accomplished by priming the body's immune system to recognize the tumor antigens so that after the primary tumor is destroyed, distant metastases will also be eradicated. Photodynamic therapy (PDT) involves the IV administration of photosensitizers followed by illumination of the tumor with red light producing reactive oxygen species leading to vascular shutdown and tumor cell death. Anti-tumor immunity is stimulated after PDT due to the acute inflammatory response, generation of tumor-specific antigens, and induction of heat-shock proteins. Combination regimens using PDT and immunostimulating treatments are likely to even further enhance post-PDT immunity. These immunostimulants are likely to include products derived from pathogenic microorganisms that are effectively recognized by Toll-like receptors and lead to upregulation of transcription factors for cytokines and inflammatory mediators. The following cascade of events causes activation of macrophages, dendritic and natural killer cells. Exogenous cytokine administration can be another way to increase PDT-induced immunity as well as treatment with a low dose of cyclophosphamide that selectively reduces T-regulatory cells. Although so far these combination therapies have only been used in animal models, their use in clinical trials should receive careful consideration.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2006
Externally publishedYes
EventBiophotonics and Immune Responses - San Jose, CA, United States
Duration: 23 Jan 200624 Jan 2006

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceBiophotonics and Immune Responses
Country/TerritoryUnited States
CitySan Jose, CA


  • Anti-tumor immunity
  • Antigen presentation
  • Cytotoxic T-cells
  • Dendritic cells
  • Photodynamic therapy
  • T regulatory cells
  • Toll-like receptors

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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