肠道微生物群和相关代谢物与乳腺癌的发生有关。有证据表明血液微生物群主要源自肠道，可能作为乳腺癌的生物标志物。我们的目的是表征血液中微生物群-肠道微生物代谢物的串扰，并开发乳腺癌的复合诊断组合。我们对 107 名乳腺癌病例和 107 名年龄配对对照的血液样本进行了 16S rRNA 基因测序和代谢组学分析。我们发现，与对照组相比，乳腺癌患者血液微生物群的α多样性有所降低。两组之间血液中微生物群和肠道微生物代谢物的分布存在显着差异，患者中九个细菌属和四种肠道微生物代谢物增加，而对照组中三十九个细菌属和两种肠道微生物代谢物增加。一些与乳腺癌相关的肠道微生物代谢物与差异性血液微生物群相关，并且进一步开发了复合微生物群-代谢物诊断组，乳腺癌曲线下面积为 0.963。这项研究强调了血液中微生物群和肠道微生物代谢物的关键作用及其在乳腺癌发生中的相互作用，以及复合诊断组合作为乳腺癌非侵入性生物标志物的潜力。乳腺癌患者血液中的肠道微生物代谢物。血液中微生物群和肠道微生物代谢物之间的广泛相关性有助于了解乳腺癌的发病机制。血液中复合微生物群-肠道微生物代谢物组的良好表现表明了一种非侵入性的乳腺癌检测方法，以及未来更好地诊断和预防乳腺癌的新策略。

Gut microbiota and associated metabolites have been linked to breast carcinogenesis. Evidences demonstrate blood microbiota primarily originates from the gut and may act as a biomarker for breast cancer. We aimed to characterize the microbiota-gut microbial metabolites cross-talk in blood and develop a composite diagnostic panel for breast cancer. We performed 16S rRNA gene sequencing and metabolomics profiling on blood samples from 107 breast cancer cases and 107 age-paired controls. We found that the alpha diversity of the blood microbiota was decreased in breast cancer compared to controls. There were significantly different profiles of microbiota and gut microbial metabolites in blood between these two groups, with nine bacterial genera and four gut microbial metabolites increased in patients, while thirty-nine bacterial genera and two gut microbial metabolites increased in controls. Some breast cancer-associated gut microbial metabolites were linked to differential blood microbiota, and a composite microbiota-metabolite diagnostic panel was further developed with an area under the curve of 0.963 for breast cancer. This study underscored the pivotal role of microbiota and gut microbial metabolites in blood and their interactions for breast carcinogenesis, as well as the potential of a composite diagnostic panel as a non-invasive biomarker for breast cancer.IMPORTANCEOur integrated analysis demonstrated altered profiles of microbiota and gut microbial metabolites in blood for breast cancer patients. The extensive correlation between microbiota and gut microbial metabolites in blood assisted the understanding of the pathogenesis of breast cancer. The good performance of a composite microbiota-gut microbial metabolites panel in blood suggested a non-invasive approach for breast cancer detection and a novel strategy for better diagnosis and prevention of breast cancer in the future.