科学家在肠道微生物组中发现引发结肠癌的罪魁祸首

  一篇发表于国际杂志Genome Medicine上的研究论文中，来自国外的研究人员通过研究指出，结肠癌患者机体肠道细菌的改变或可帮助揭示某些毒力细菌和结肠癌的发病直接相关，文章中研究者鉴别出了一种新型的细菌毒力特性，者或可帮助医生们预测患者机体肠道细菌的改变如何来影响癌症患者的预后。
  人类肠道的微生物组，即众多微生物的集合，微生物组和不同的细菌会共同维持一个健康的肠道，而且肠道微生物也被认为在结肠癌的发展中扮演着重要的角色；此前有研究发现结肠癌患者肠道的微生物组的细菌发生着明显变化，即肿瘤处的细菌多样性较高，而且相比健康组织而言肿瘤患处的致病细菌的水平较高。尽管研究者揭开了致病性细菌和结肠癌的关系，但目前研究者并不清楚其具体关联。
  研究者Michael Burns教授指出，我们在结肠癌患者机体的肠道中鉴别出了两种毒力细菌的存在，而且通过对这些病原体相似性的分析，以及肠道微生物组的分子我们鉴别出了结肠癌的单一特性，这或许可以帮助开发治疗结肠癌的新型疗法。本文研究首次在结肠癌的肿瘤微环境中发现了细菌基因的毒力潜力，而且肠道微生物组的特殊基因可以在44种原发性肿瘤及44种病人匹配的正常结肠组织中进行预测来帮助分析广泛的微生物学功能。
  通过分析肠道微生物组的主要改变或可帮助研究人员对不同细菌所扮演的角色进行分类，最后研究者表示他们还需要进行更多研究来评估肠道细菌和结肠癌发展之间的关联，这或许会为开发新型治疗结肠癌的特殊疗法提供思路。（转化医学网360zhyx.com）
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转化医学网推荐的原文摘要：

Virulence genes are a signature of the microbiome in the colorectal tumor microenvironment
Genome Medicine     doi:10.1186/s13073-015-0177-8
Michael B. Burns12*, Joshua Lynch12, Timothy K. Starr134, Dan Knights56 and Ran Blekhman12*
Background The human gut microbiome is associated with the development of colon cancer, and recent studies have found changes in the microbiome in cancer patients compared to healthy controls. Studying the microbial communities in the tumor microenvironment may shed light on the role of host-bacteria interactions in colorectal cancer. Here, we highlight the major shifts in the colorectal tumor microbiome relative to that of matched normal colon tissue from the same individual, allowing us to survey the microbial communities at the tumor microenvironment and provides intrinsic control for environmental and host genetic effects on the microbiome. Methods We sequenced the microbiome in 44 primary tumor and 44 patient-matched normal colon tissues to determine differentially abundant microbial taxa. These data were also used to functionally characterize the microbiome of the cancer and normal sample pairs and identify functional pathways enriched in the tumor-associated microbiota. Results We find that tumors harbor distinct microbial communities compared to nearby healthy tissue. Our results show increased microbial diversity at the tumor microenvironment, with changes in the abundances of commensal and pathogenic bacterial taxa, including Fusobacterium and Providencia. While Fusobacterium has previously been implicated in colorectal cancer, Providencia is a novel tumor-associated agent, which has not been identified in previous studies. Additionally, we identified a clear, significant enrichment of predicted virulence-associated genes in the colorectal cancer microenvironment, likely dependent upon the genomes of Fusobacterium and Providencia. Conclusions This work identifies bacterial taxa significantly correlated with colorectal cancer, including a novel finding of an elevated abundance of Providencia in the tumor microenvironment. We also describe the predicted metabolic pathways and enzymes differentially present in the tumor associated microbiome, and show an enrichment of virulence-associated bacterial genes in the tumor microenvironment. This predicted virulence enrichment supports the hypothesis that the microbiome plays an active role in colorectal cancer development and/or progression. Our results provide a starting point for future prognostic and therapeutic research with the potential to improve patient outcomes.