Brainard G C, Kavet R, Kheifets L I
Department of Neurology, Jefferson Medical College, Philadelphia, Pennsylvannia 19107, USA. george.brainardemail.tju.edu.
J Pineal Res. 1999 Mar;26(2):65-100. doi: 10.1111/j.1600-079x.1999.tb00568.x.
Worldwide, breast cancer is the most common malignancy accounting for 20-32% of all female cancers. This review summarizes the peer-reviewed, published data pertinent to the hypothesis that increased breast cancer in industrialized countries is related to the increased use of electricity [Stevens, R.G., S. Davis 1996]. That hypothesis specifically proposes that increased exposure to light at night and electromagnetic fields (EMF) reduce melatonin production. Because some studies have shown that melatonin suppresses mammary tumorigenesis in rats and blocks estrogen-induced proliferation of human breast cancer cells in vitro, it is reasoned that decreased melatonin production leads to increased risk of breast cancer. To evaluate this hypothesis, the paper reviews epidemiological data on associations between electricity and breast cancer, and assesses the data on the effects of EMF exposure on melatonin physiology in both laboratory animals and humans. In addition, the results on the effects of melatonin on in vivo carcinogenesis in animals are detailed along with the controlled in vitro studies on melatonin's effects on human breast cancer cell lines. The literature is evaluated for strength of evidence, inter-relationships between various lines of evidence, and gaps in our knowledge. Based on the published data, it is currently unclear if EMF and electric light exposure are significant risk factors for breast cancer, but further study appears warranted. Given the ubiquitous nature of EMF and artificial light exposure along with the high incidence of breast cancer, even a small risk would have a substantial public health impact.
在全球范围内，乳腺癌是最常见的恶性肿瘤，占所有女性癌症的20%-32%。本综述总结了经同行评审并发表的与以下假设相关的数据：工业化国家乳腺癌发病率的增加与电力使用的增加有关[史蒂文斯，R.G.，S.戴维斯，1996年]。该假设具体提出，夜间光照和电磁场（EMF）暴露的增加会减少褪黑素的分泌。因为一些研究表明，褪黑素在大鼠中可抑制乳腺肿瘤发生，并在体外阻断雌激素诱导的人乳腺癌细胞增殖，所以有理由认为褪黑素分泌减少会导致乳腺癌风险增加。为评估这一假设，本文回顾了关于电力与乳腺癌关联的流行病学数据，并评估了实验室动物和人类中EMF暴露对褪黑素生理影响的数据。此外，还详细介绍了褪黑素对动物体内致癌作用的影响结果以及褪黑素对人乳腺癌细胞系影响的对照体外研究。对文献的证据强度、各种证据之间的相互关系以及我们知识上的空白进行了评估。根据已发表的数据，目前尚不清楚EMF和光照暴露是否为乳腺癌的重要风险因素，但似乎有必要进一步研究。鉴于EMF和人工光照暴露的普遍性以及乳腺癌的高发病率，即使是很小的风险也会对公众健康产生重大影响。
