In this regard, pro-oxidant agents—such as high-dose intravenous vitamin C and auranofin, an FDA-approved drug for rheumatoid arthritis that primarily inhibits thioredoxin reductase—may serve as effective radiosensitizers or chemosensitizers by further destabilizing the cellular redox equilibrium. The gene discussed is PRDX5; the disease is rheumatoid arthritis.