PLoS ONE：牛机体的病毒能否引发人类乳腺癌的发生？

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图片来源：medicalxpress.com

来自加利福尼亚大学的科学家近日通过研究首次发现感染牛白血病病毒和人类乳腺癌发病之间的神秘关联，相关研究发表于国际杂志PLoS ONE上，文章中研究者对239名女性患者的乳腺组织进行分析，对比了乳腺癌患者的样本组织和无疾病史但感染牛白血病病毒(BLV)个体的组织样本的差异，结果发现，59%的乳腺癌患者机体样本中都检测出了BLV的病毒DNA，随后通过进一步对比，研究者还发现，在从未患过乳腺癌的女性个体的组织样本中有29%的样本都暴露于BLV中。

研究者Gertrude Buehring说道，此前很多研究都比较惊讶BLV感染和乳腺癌的关系，但更为重要的一点就是本文研究结果并不能证明病毒是引发癌症的罪魁祸首；然而相关研究对于下一步研究更为重要，我们需要确定的是到底患者是在病毒感染前还是感染后发生的乳腺癌。

牛白血病病毒可以感染牛类的血细胞及哺乳动物组织，而这种反转录病毒可以通过感染的血液和牛奶在家畜中传播，但仅有低于5%的感染动物会发病。早在2007年美国农业部的一项调查就表明，对500多只奶牛进行检测就发现100%的BLV病毒抗体阳性；目前研究人员并不确定是否BLV存在于人类机体中，去年发表在国际杂志Emerging Infectious Diseases上的一篇报道中，研究者Buehring就推翻了此前的认为病毒并不会在人类之间传播的认识。

早在20世纪70年代进行的研究并不有发现人类受BLV感染的证据，但如今研究者所采用的技术相当敏感，但仍然很难推翻之前建立的认知，即认为BLV不会在人间传播，因此这就很少激励养牛业来重新设置检测BLV的步骤。而在本文研究中，研究者发现BLV有很大的可能性存在于乳腺癌组织中，而对数据进行统计学分析后，研究者发现，BLV存在时个体患乳腺癌的风险是病毒不存在时的3.1倍，而且这种优势比要明显高于任何已经报道的引发乳腺癌的风险因素，比如肥胖、酒精消耗及绝经后激素的使用等。

目前已有病毒源性的癌症范例，比如乙型肝炎病毒就是引发肝癌的重要致癌因子，而且人类乳头瘤病毒也是引发宫颈癌的因子，但值得注意的是，研究者已经开发出了疫苗来帮助预防个体患病毒相关的癌症。

研究者Buehring说道，如果BLV被证明是引发乳腺癌的原因，那么我们或许就会改变对乳腺癌的控制策略，我们或许会将重点转移到如何去预防乳腺癌上，而不是去寻找治疗的方法。最后研究者强调说，本文研究并不能确定BLV感染乳腺组织的机制，但病毒的确可以通过未灭菌的牛奶或未煮熟的肉类来感染机体。

来源：生物谷

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Exposure to Bovine Leukemia Virus Is Associated with Breast Cancer: A Case-Control Study

Gertrude Case Buehring , Hua Min Shen, Hanne M. Jensen, Diana L. Jin, Mark Hudes, Gladys Block


Background

Age, reproductive history, hormones, genetics, and lifestyle are known risk factors for breast cancer, but the agents that initiate cellular changes from normal to malignant are not understood. We previously detected bovine leukemia virus (BLV), a common oncogenic virus of cattle, in the breast epithelium of humans. The objective of this study was to determine whether the presence of BLV DNA in human mammary epithelium is associated with breast cancer.


Methods

This was a case-control study of archival formalin fixed paraffin embedded breast tissues from 239 donors, received 2002–2008 from the Cooperative Human Tissue Network. Case definition as breast cancer versus normal (women with no history of breast cancer) was established through medical records and examination of tissues by an anatomical pathologist. Breast exposure to BLV was determined by in situ-PCR detection of a biomarker, BLV DNA, localized within mammary epithelium.


Results

The frequency of BLV DNA in mammary epithelium from women with breast cancer (59%) was significantly higher than in normal controls (29%) (multiply- adjusted odds ratio = 3.07, confidence interval = 1.66–5.69, p = .0004, attributable risk = 37%). In women with premalignant breast changes the frequency of BLV DNA was intermediate (38%) between that of women with breast cancer and normal controls (p for trend < .001).


Conclusions

Among the specimens in this study, the presence of amplified BLV DNA was significantly associated with breast cancer. The odds ratio magnitude was comparable to those of well-established breast cancer risk factors related to reproductive history, hormones, and lifestyle and was exceeded only by risk factors related to genetics (familial breast cancer), high dose ionizing radiation, and age. These findings have the potential for primary and secondary prevention of breast cancer.

http://journals.plos.org/plosone ... ournal.pone.0134304

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要是真的，那可得重创牛奶业啊

bigben446

【标题】：Bovine leukemia virus DNA in human breast tissue
【作者】：Buehring, G. C.; Shen, H. M.; Jensen, H. M. (...)
【来源】：Emerg Infect Dis, 2014, 20(5), 772-782
【摘要】：Bovine leukemia virus (BLV), a deltaretrovirus, causes B-cell leukemia/lymphoma in cattle and is prevalent in herds globally. A previous finding of antibodies against BLV in humans led us to examine the possibility of human infection with BLV. We focused on breast tissue because, in cattle, BLV DNA and protein have been found to be more abundant in mammary epithelium than in lymphocytes. In human breast tissue specimens, we identified BLV DNA by using nested liquid-phase PCR and DNA sequencing. Variations from the bovine reference sequence were infrequent and limited to base substitutions. In situ PCR and immunohistochemical testing localized BLV to the secretory epithelium of the breast. Our finding of BLV in human tissues indicates a risk for the acquisition and proliferation of this virus in humans. Further research is needed to determine whether BLV may play a direct role in human disease.