Light has been used to treat diseases for hundreds of years. Convenient and powerful light sources such as lasers make photomedicine a major branch in diseases treatment and detection. Originally, light was often used for local treatment, using photomechanical, photochemical, photothermal reactions and photomodulation as the major mechanisms. More and more investigators have become interested in the systemic effects of light, particularly in its effects on immune systems. Much work has been done to activate and/or enhance the host immune system to combat cancer, either using light as a direct tool or as an adjuvant method. Light has long been used for assisting disease detection and diagnosis. Advances in light technology have made photo-diagnostics ever more precise spatially and temporally. Many techniques facilitate observation of bio-molecule interactions and other biological processes at the cellular level, hence providing opportunities to detect and monitor immune activities. This manuscript will review recent photo-immunological research in treatment of cancer. The recent development of combination therapies involving lasers will be presented. Specifically, the results of cancer treatment using laser photothermal interaction, either with or without additional immunological stimulation will be discussed. The immunological effects of photodynamic therapy (PDT), and of its combination with immunotherapy in cancer treatment will also be discussed. Much interest has been recently concentrated in the immunological responses after laser treatment. Such responses at cellular and molecular levels will be discussed. The effect of these treatment modalities on the distant metastases also showed promise of light induced antitumor immunity. The combination therapy and induced immunological responses appear to be the key for long-term control of tumors.
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