Reactive Species from Cold Atmospheric Plasma: Implications for Cancer Therapy

Cold atmospheric plasmas (CAP) formed in air generate reactive oxygen and nitrogen species (RONS). RONS are biologically and therapeutically active agents and experimental evidence suggests that air plasmas shrink tumors by increasing oxidative and nitrosative stress on neoplastic tissue. Most mainline anti-cancer therapies - including ionizing radiation and chemotherapies - also operate primarily via this pro-oxidant, oxidative, and nitrosative stress mechanism. The main disadvantage of these conventional therapies is the development of treatment-resistant cells. A key question for plasma cancer therapies is therefore whether or not cold plasma will lead to similar oxidative stress resistance. However, there are hints that combining nitrosative stress with oxidative stress via air plasma might avoid this problem. Plasma-based cancer treatment may be a powerful and practical anti-cancer agent, acting either alone or in combination with other therapies.