GSTM3 (glutathione S-transferase mu 3) is a phase II detoxifying enzyme that catalyzes glutathione conjugation to exogenous and endogenous electrophiles 1. The protein functions in cellular detoxification and xenobiotic metabolism, with particular relevance at tissue barriers including the testis and brain. Beyond canonical detoxification roles, GSTM3 has emerged as a critical regulator of ferroptosis—a form of iron-dependent cell death. In hepatocellular carcinoma, zone 3-specific GSTM3 expression is required for efficient tumor initiation, partly through ferroptosis inhibition 2. Conversely, in nasopharyngeal carcinoma, GSTM3 paradoxically enhances radiosensitivity by promoting radiation-induced ferroptosis through mechanisms involving USP14/FASN stabilization and GPX4 suppression 3. Similarly, GSTM3 inhibition by the natural compound echinatin triggers ferroptosis in cutaneous squamous cell carcinoma 4. GSTM3 also regulates reactive oxygen species levels and oxidative stress responses 1. Genetic polymorphisms in GSTM3 associates with cancer risk; the A/B polymorphism is associated with decreased head and neck cancer risk 5. Higher GSTM3 levels correlate with asymptomatic disease in parasitic infection contexts 6. These findings indicate GSTM3 functions as a context-dependent modulator of cell death pathways relevant to cancer development and treatment.