Malondialdehyde and Oxidative Stress in Cancer: Biological Insights and Clinical Perspectives.

Malondialdehyde (MDA) is one of the main end-products of lipid peroxidation (LPO) and represents a widely investigated marker of oxidative stress (OS) and oxidative tissue damage. Beyond its role as a measurable byproduct of polyunsaturated fatty acid peroxidation, MDA can interact with proteins and nucleic acids, generating adducts that may contribute to mutagenic, genotoxic, and cytotoxic events involved in carcinogenesis and tumor progression. This narrative review summarizes current evidence on the role of MDA in cancers, including breast, lung, head and neck, colorectal, cervical, and cutaneous tumors. Across these cancer types, increased circulating or tissue MDA levels have frequently been associated with enhanced LPO, impaired antioxidant defenses, tumor burden, advanced disease stage, aggressive histopathological features, treatment-related oxidative injury, and, in selected studies, poorer clinical outcomes. MDA-derived DNA adducts may further reflect oxidative DNA damage and provide mechanistic insight into the relationship between chronic redox imbalance, inflammation, and malignant transformation. However, MDA remains a non-specific biomarker influenced by age, smoking, diet, metabolic disorders, systemic inflammation, comorbidities, treatment exposure, and analytical methodology. Current evidence therefore supports MDA as a biologically relevant indicator of oxidative damage rather than a validated stand-alone diagnostic, prognostic, or therapeutic biomarker. Larger prospective studies using standardized and specific analytical methods are needed to clarify its clinical utility and to integrate MDA within broader redox biomarker panels.