The gastrointestinal tract harbors most of the microbiota associated with humans. In recent years, there has been a surge of interest in assessing the relationships between the gut microbiota and several gut alterations, including colorectal cancer. Changes in the gut microbiota in patients suffering colorectal cancer suggest a possible role of host-microbe interactions in the origin and development of this malignancy and, at the same time, open the door for novel ways of preventing, diagnosing, or treating this disease. In this review we survey current knowledge on the healthy microbiome of the gut and how it is altered in colorectal cancer and other related disease conditions. In describing past studies we will critically assess technical limitations of different approaches and point to existing challenges in microbiome research. We will have a special focus on host-microbiome interaction mechanisms that may be important to explain how dysbiosis can lead to chronic inflammation and drive processes that influence carcinogenesis and tumor progression in colon cancer. Finally, we will discuss the potential of recent developments of novel microbiota-based therapeutics and diagnostic tools for colorectal cancer.

胃肠道具有与人类有关的大多数微生物群。近年来，人们对评估肠道菌群与几种肠道改变（包括结直肠癌）之间关系的兴趣激增。大肠癌患者肠道菌群的变化表明，宿主-微生物相互作用可能在这种恶性肿瘤的发生和发展中发挥作用，同时，为预防，诊断或治疗这种疾病的新方法打开了大门。在这篇综述中，我们调查了当前关于肠道健康微生物组的知识，以及它在结肠直肠癌和其他相关疾病中的变化情况。在描述过去的研究时，我们将严格评估不同方法的技术局限性，并指出微生物组研究中存在的挑战。我们将特别关注宿主-微生物组的相互作用机制，这可能对于解释菌群异常如何导致慢性炎症并驱动影响结肠癌致癌性和肿瘤进展的过程很重要。最后，我们将讨论基于新型微生物群的大肠癌治疗和诊断工具的最新发展潜力。