Blask David E
Laboratory of Chrono-Neuroendocrine Oncology, Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA.
Sleep Med Rev. 2009 Aug;13(4):257-64. doi: 10.1016/j.smrv.2008.07.007. Epub 2008 Dec 17.
The pineal hormone melatonin is involved in the circadian regulation and facilitation of sleep, the inhibition of cancer development and growth, and the enhancement of immune function. Individuals, such as night shift workers, who are exposed to light at night on a regular basis experience biological rhythm (i.e., circadian) disruption including circadian phase shifts, nocturnal melatonin suppression, and sleep disturbances. Additionally, these individuals are not only immune suppressed, but they are also at an increased risk of developing a number of different types of cancer. There is a reciprocal interaction and regulation between sleep and the immune system quite independent of melatonin. Sleep disturbances can lead to immune suppression and a shift to the predominance in cancer-stimulatory cytokines. Some studies suggest that a shortened duration of nocturnal sleep is associated with a higher risk of breast cancer development. The relative individual contributions of sleep disturbance, circadian disruption due to light at night exposure, and related impairments of melatonin production and immune function to the initiation and promotion of cancer in high-risk individuals such as night shift workers are unknown. The mutual reinforcement of interacting circadian rhythms of melatonin production, the sleep/wake cycle and immune function may indicate a new role for undisturbed, high quality sleep, and perhaps even more importantly, uninterrupted darkness, as a previously unappreciated endogenous mechanism of cancer prevention.
松果体激素褪黑素参与昼夜节律调节和促进睡眠、抑制癌症发展和生长以及增强免疫功能。经常在夜间接触光线的个体，如夜班工作者，会经历生物节律（即昼夜节律）紊乱，包括昼夜相移、夜间褪黑素抑制和睡眠障碍。此外，这些个体不仅免疫功能受到抑制，而且患多种不同类型癌症的风险也会增加。睡眠和免疫系统之间存在一种相互作用和调节，这与褪黑素无关。睡眠障碍可导致免疫抑制，并使促癌细胞因子占主导地位。一些研究表明，夜间睡眠时间缩短与患乳腺癌的风险较高有关。对于夜班工作者等高危个体，睡眠障碍、夜间光照导致的昼夜节律紊乱以及褪黑素分泌和免疫功能的相关损害对癌症发生和发展的相对个体贡献尚不清楚。褪黑素分泌、睡眠/觉醒周期和免疫功能相互作用的昼夜节律相互加强，这可能表明未受干扰的高质量睡眠，甚至更重要的是不间断的黑暗，作为一种以前未被重视的内源性癌症预防机制具有新的作用。
