Anticancer Effects and uses of Melatonin: A Review

Melatonin (N-acetyl-5-methoxytryptamine, MLT) is a naturally occurring hormone secreted by the pineal gland. Clinical evidence suggests that MLT may have a possible role in the treatment of cancer, where MLT presents many oncostatic properties in a wide variety of tumors, utilizing multiple and converging mechanisms. It is a potent anti-oxidative agent; its circadian rhythm-regulating properties are crucial for orchestrating patterns of hormone secretion, the imbalance of which is implicated in a wide range of hormonedependent cancers of the reproductive organs. Recent advances in cancer treatment can offer therapeutic alternatives that could reduce the severity of unwanted side effects. Several observational studies have demonstrated a relationship between long-term disruption of circadian rhythm with decreased MLT secretion and increased cancer risk, whilst clinical evidence supports the possible benefits from MLT on the survival in patients with a range of cancers. This review will address some of the multiple anticancer properties of MLT, with a particular focus on the mechanisms counteracting tumor occurrence, growth, and development. Recent research into the oncostatic effects of MLT and the mechanisms of action explaining its efficiency for tumor regulation are summarized in this review and suggestions for the therapeutic use of MLT will be presented.