From Metal Stress to Regulated Cell Death: An Evidence Framework for Ferroptosis–Cuproptosis Crosstalk in Cancer

Resistance to apoptosis, metabolic plasticity, and redox adaptation are major contributors to cancer progression and treatment failure. Ferroptosis and cuproptosis have therefore emerged as metal-dependent forms of regulated cell-death programs with potential relevance for tumours that survive conventional therapy. Ferroptosis is driven by iron-dependent phospholipid peroxidation when glutathione peroxidase 4 (GPX4)-dependent and parallel antioxidant systems fail, whereas cuproptosis depends on mitochondrial copper engagement of lipoylated tricarboxylic-acid-cycle proteins, lipoylated-protein aggregation, iron–sulfur protein destabilization, and proteotoxic stress. This review integrates the molecular basis, genetic architecture, long non-coding RNA (lncRNA)-mediated regulation, mechanistic crosstalk, and therapeutic implications of ferroptosis and cuproptosis in cancer. It emphasizes a critical evidence hierarchy: expression association, computational signature construction, metal accumulation, reactive oxygen species (ROS) generation, or reduced viability should not be interpreted as pathway dependency without pathway-defining biochemical endpoints and rescue experiments. The most credible translational opportunities will depend on functional stratification, tumour-selective delivery, and pharmacodynamic confirmation that distinguishes pathway-defined ferroptosis or cuproptosis from nonspecific metal-induced and oxidative cytotoxicity.