Magnesium and Cancer Immunotherapy: A Narrative Practical Review

Magnesium (Mg²⁺) has garnered the attention of oncologists due to its wide range of biological functions and frequent use as a complementary or integrative agent. In this study, a concise narrative review of the complex relationships between Mg²⁺ and immunotherapy for human malignancies is presented, in addition to a possible future therapeutic scenario. Pertinent full-text articles were thoroughly examined, and the most relevant ones were selected for inclusion in this review. A significant body of preclinical studies highlights the role of Mg²⁺ in regulating immune function, particularly in cytotoxic effector cells, underscoring the importance of maintaining adequate Mg²⁺ homeostasis mainly when immune-modulating agents are used in clinical practice. Whether serum Mg²⁺ levels influence the clinical outcomes of cancer patients treated with immune checkpoint blocker treatment remains to be fully elucidated. However, over the last decade, an increasing amount of data suggests that maintaining normal or slightly elevated serum levels of Mg²⁺ may enhance the response to immune therapy and even improve survival outcomes. New potential modulators of the tumor microenvironment and response to immunotherapy, such as injectable gels and metal-based biomaterials, are discussed.