Melatonin and Breast Cancer: A Review Article.

Breast cancer is one of the most common causes of death all over the world. Therapeutic options applied to the patients include surgery, chemotherapy, and radiotherapy. However, far advanced disease often leads to chemoresistance and toxicity. Innovative therapies are needed to address these challenges. Melatonin has the potential to prevent and treat cancer, as it has been revealed in numerous clinical studies. Melatonin is a nontoxic agent that is mostly produced in the pineal gland, inducing various mechanisms of action such as the induction of apoptosis, antiangiogenic, antiproliferative, and metastasis-inhibitory effects. Therefore, melatonin increases therapeutic sensitivity when combined with conventional medication in breast cancer. Melatonin (3-20 mg/day) may reduce breast cancer cell growth in preclinical studies and enhance chemotherapy efficacy. Small human trials suggest potential benefits, but larger studies are needed. Higher doses (≥20 mg/day) are sometimes used alongside chemotherapy. This manuscript reviews research that has demonstrated the antitumor properties of melatonin, thereby focusing on its actions on angiogenesis, apoptosis, metastasis, and antiproliferative properties. We also discuss recent advances in the understanding of the actions of melatonin on epigenetic mechanisms (especially DNA methylation) and telomere length. The data in this review were obtained from journal articles up to May 2024. Regarding the study, Google Scholar and ScienceDirect were used as engines to search for open access. We searched the ISI, Pubmed and Scopus as valid external databases, and as internal databases, ISC and Iran medex. By finding mean keywords such as 'breast cancer', 'estrogen', 'melatonin', 'cell death', 'cell proliferation', 'telomerase' and 'DNA methylation', we reached to the formula with maximum collectivity in searching, then equivalent terms were found by Mesh database. The review also covers recent clinical investigations of melatonin in breast cancer.