Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G2W1, Canada.
Genes (Basel). 2019 Jul 26;10(8):566. doi: 10.3390/genes10080566.
While epidemiological studies performed in Asian countries generally show that high levels of dietary soy are associated with reduced breast cancer risk, studies in Western countries have typically failed to show this correlation. In an attempt to model the preventative actions of soy on mammary tumor development, rodent models have been employed. Thirty-four studies were identified that evaluated the impact of soy products or purified soy isoflavones on mammary tumor initiation (studies evaluating established mammary tumors or mammary tumor cell lines were not included) and these studies were separated into mammary tumors induced by chemical carcinogens or transgenic expression of oncogenes based on the timing of soy administration. Regardless of when soy-based diets or purified isoflavones were administered, no consistent protective effects were observed in either carcinogen-induced or oncogene-induced mammary tumors. While some studies demonstrated that soy or purified isoflavones could reduce mammary tumor incidence, other studies showed either no effect or tumor promoting effects of soy products or isoflavones. Most importantly, only five studies found a decrease in mammary tumor incidence and six studies observed a decrease in tumor multiplicity, two relevant measures of the tumor preventative effects of soy or isoflavones. The variable outcomes of the studies examined were not completely surprising given that few studies employed the same experimental design. Future studies should be carefully designed to more accurately emulate soy consumption observed in Asian cultures including lifetime exposure to less refined soy products and potentially the incorporation of multigenerational feeding studies.
虽然在亚洲国家进行的流行病学研究普遍表明，高膳食大豆摄入量与降低乳腺癌风险有关，但西方国家的研究通常未能显示出这种相关性。为了模拟大豆对乳腺肿瘤发展的预防作用，已经使用了啮齿动物模型。确定了 34 项研究，评估了大豆制品或纯化大豆异黄酮对乳腺肿瘤起始的影响（未包括评估已建立的乳腺肿瘤或乳腺肿瘤细胞系的研究），这些研究根据大豆给药的时间分为化学致癌物诱导的乳腺肿瘤或致癌基因过表达诱导的乳腺肿瘤。无论何时给予基于大豆的饮食或纯化的异黄酮，在化学致癌物或致癌基因诱导的乳腺肿瘤中均未观察到一致的保护作用。虽然一些研究表明大豆或纯化的异黄酮可以降低乳腺肿瘤的发生率，但其他研究表明大豆制品或异黄酮没有影响或具有促进肿瘤的作用。最重要的是，只有五项研究发现乳腺肿瘤发生率降低，六项研究观察到肿瘤多发性降低，这是评估大豆或异黄酮肿瘤预防作用的两个相关措施。考虑到很少有研究采用相同的实验设计，因此检查中研究结果的差异并不完全令人惊讶。未来的研究应精心设计，更准确地模拟亚洲文化中观察到的大豆消费，包括终生接触不太精制的大豆制品，并可能纳入多代饲养研究。
