Reactive oxygen species (ROS) act as double-edged swords in cancer biology—facilitating tumor growth, survival, and metastasis at moderate levels while inducing oxidative damage and cell death when exceeding cellular buffering capacity. To survive under chronic oxidative stress, cancer cells rely on robust antioxidant systems such as the glutathione (GSH) and thioredoxin (Trx), and superoxide dismutases (SODs). These systems maintain redox homeostasis and sustain ROS-sensitive signaling pathways including MAPK/ERK, PI3K/Akt/mTOR, NF-κB, STAT3, and HIF-1α. Targeting the antioxidant defense mechanisms of cancer cells has emerged as a promising therapeutic strategy. Inhibiting the glutathione system induces ferroptosis, a non-apoptotic form of cell death driven by lipid peroxidation, with compounds like withaferin A and altretamine showing strong preclinical activity. Disruption of the Trx system by agents such as PX-12 and dimethyl fumarate (DMF) impairs redox-sensitive survival signaling. Trx reductase inhibition by auranofin or mitomycin C further destabilizes redox balance, promoting mitochondrial dysfunction and apoptosis. SOD1 inhibitors, including ATN-224 and disulfiram, selectively enhance oxidative stress in tumor cells and are currently being tested in clinical trials. Mounting preclinical and clinical evidence supports redox modulation as a cancer-selective vulnerability. Pharmacologically tipping the redox balance beyond the threshold of cellular tolerance offers a rational and potentially powerful approach to eliminate malignant cells while sparing healthy tissue, highlighting novel strategies for targeted cancer therapy at the interface of redox biology and oncology.

Reactive oxygen species (ROS) are versatile determinants of cell fate, tipping the balance between survival and death. By exceeding critical thresholds or perturbing compartment-specific signaling, ROS can initiate, modulate, or suppress regulated cell death (RCD). Importantly, their influence extends across the full spectrum of currently characterized RCD modalities. 19 distinct forms of cell death—including both long-established and recently described entities—are shaped by ROS, either as triggers, modulators, or inhibitors. Beyond pathway-specific effects, ROS promote crosstalk between death programs, enabling switches from one mode to another and determining whether outcomes are inflammatory or non-inflammatory. By systematically integrating 19 RCD types, the unifying role of ROS emerges as both gatekeeper and connector of diverse death pathways. Such a comprehensive perspective underscores the centrality of redox imbalance in cell fate control and highlights its broader implications for inflammation and disease.