ABSTRACT
Three centuries ago, the French philosopher René Descartes [1] described the pineal gland as “the seat of the soul,” but it was not until the late 1950s that melatonin, the principal secretory product of the pineal gland was identi£ed [2]. There is now evidence that melatonin may have a role in several biological functions, among which are circadian rhythms, sleep, mood, reproduction, and aging [3-5]. Moreover, as a pharmaceutical drug, melatonin is thought to be bene£cial in some pathological conditions[6-8].Namely, there is now compelling evidence that melatonin may reduce the incidence and the growth of human tumors. However, uncertainties and doubts still surround the physiological mechanisms and the biochemical pathways through which melatonin exerts its antineoplastic effects [9].
