乳腺癌是全球女性中最常见的恶性肿瘤。癌症的成因是多因素的。早期发现和适当的治疗可以改善生存的机会。最近的研究表明，微生物群影响乳腺癌。不同的微生物特征在乳腺微生物中被鉴定出来，具有不同的模式，取决于阶段和生物亚组。人类的消化系统含有大约100万亿个细菌。肠道微生物是一个新兴的研究领域，与许多疾病的具体生物过程相关，包括心血管疾病、肥胖症、糖尿病、脑部疾病、类风湿性关节炎和癌症。在本综述文章中，我们讨论微生物群对乳腺癌的影响，重点关注肠道微生物对乳腺癌微环境的调节。最终，免疫疗法如何影响乳腺癌微生物群和进一步的乳腺和微生物群轴的临床试验可能是更好预测乳腺癌风险和预后的重要组成部分。

Breast cancer is the most common malignancy in women worldwide. The cause of cancer is multifactorial. An early diagnosis and the appropriate treatment of cancer can improve the chances of survival. Recent studies have shown that breast cancer is influenced by the microbiota. Different microbial signatures have been identified in the breast microbiota, which have different patterns depending on the stage and biological subgroups. The human digestive system contains approximately 100 trillion bacteria. The gut microbiota is an emerging field of research that is associated with specific biological processes in many diseases, including cardiovascular disease, obesity, diabetes, brain disease, rheumatoid arthritis, and cancer. In this review article, we discuss the impact of the microbiota on breast cancer, with a primary focus on the gut microbiota's regulation of the breast cancer microenvironment. Ultimately, updates on how immunotherapy can affect the breast cancer-based microbiome and further clinical trials on the breast and microbiome axis may be an important piece of the puzzle in better predicting breast cancer risk and prognosis.