Plasma, cancer, immunity

Abstract

Albeit heavily investigated for several decades already, the importance of the immune system in targeting cancer has received wide clinical attention only in recent years. This is partly because of long-standing rather traditional concepts on tumor biology on the one hand and the complexity of the immune system and its processes on the other. The viewpoint of evaluating existing and emerging approaches in oncology based on toxicity to tumors and the ability to engage antitumor-immunity is gaining ground across several disciplines. Along those lines, cold physical plasma was suggested as potential anticancer tool more than a decade ago, but solid evidence of the immune system playing a role in plasma cancer treatment only emerged in recent years. Moreover, plasma may support cancer immunotherapies in the future. Cancer immunotherapies are systemic treatments with biologicals that were reported to synergize with existing local physical modalities before, such as radiotherapy and photodynamic therapy. This review outlines key concepts in oncology, immunology, and tumor therapy, links them to plasma research, and discusses immuno-oncological consequences. Finally, promising future clinical applications are summarized. Synoptically, first scientific evidence supports an immuno-oncological dimension of plasma cancer treatment in selected instances, but robust clinical evidence is still lacking. More basic and clinical research is needed to determine the immuno-molecular mechanisms and detailed plasma application modalities to facilitate real patient benefit in the long term.

Synergistic effect of cold gas plasma and experimental drug exposure exhibits skin cancer toxicity in vitro and in vivo

“…It is understood, however, that most patients die due to hard-to-reach metastasis and not because of topical tumor burden in the skin, which would be relatively simple to remove surgically. As recently reviewed, systemic action could be achieved by the immuno-stimulative potential cold gas plasma technology displayed in several syngeneic animal models [22] . In addition, a small cohort of patients with irresectable SCC of the head and neck or palliative patient cohorts with infected superficial tumors may benefit from combined drug and cold gas plasma therapy [76] .…”

“…In recent years, the technology has been increasingly investigated in oncology. Many in vitro studies and a constantly growing number of in vivo animal studies support the potential use of cold gas plasma in cancer treatment [21] , [22] . In a series of patient case reports, cold gas plasma was applied in the palliative setting to reduce the microbial load and typical fetid odor of locally advanced and ulcerating squamous cell carcinomas of the head and neck.…”

Multi-Cohort Transcriptomic Profiling of Medical Gas Plasma-Treated Cancers Reveals the Role of Immunogenic Cell Death

“…We hypothesized that transcriptional aberrations are reproducible for certain dysregulated genes that are associated with common molecular activation mechanisms, leveraging the biological and technical heterogeneities of the cancer cells and experimental protocols. A particular emphasis was put on immunological phenomena, which are frequently observed in tumor animal models in the field of plasma medicine [ 29 ].…”

Cold Physical Plasma Toxicity in Breast and Oral Squamous Carcinoma In Vitro and in Patient-Derived Cancer Tissue Ex Vivo

“…It is known that endogenous and exogenous reactive oxygen species (ROS) can have various effects on cancer cells and immune cells within the tumor microenvironment (TME) [9][10][11]. Cold physical plasma is a partially ionized gas that can generate various types of ROS, which have been shown to induce ROS, toxicity, and immunogenicity in tumor cells, reducing tumor growth and increasing cell death [12][13][14]. Additionally, physical plasma has been shown to increase the expression of specific chemokines and cytokines within the TME, which can attract immune cells such as T cells and natural killer cells to the tumor site, such as melanoma in vivo and in patient-derived melanoma tissues ex vivo [15,16].…”