Comprehensive profiles and diagnostic value of menopausal-specific gut microbiota in premenopausal breast cancer

In Western countries, breast cancer tends to occur in older postmenopausal women. However, in Asian countries, the proportion of younger premenopausal breast cancer patients is increasing. Increasing evidence suggests that the gut microbiota plays a critical role in breast cancer. However, studies on the gut microbiota in the context of breast cancer have mainly focused on postmenopausal breast cancer. Little is known about the gut microbiota in the context of premenopausal breast cancer. This study aimed to comprehensively explore the gut microbial profiles, diagnostic value, and functional pathways in premenopausal breast cancer patients. Here, we analyzed 267 breast cancer patients with different menopausal statuses and age-matched female controls. The α-diversity was significantly reduced in premenopausal breast cancer patients, and the β-diversity differed significantly between breast cancer patients and controls. By performing multiple analyses and classification, 14 microbial markers were identified in the different menopausal statuses of breast cancer. Bacteroides fragilis was specifically found in young women of premenopausal statuses and Klebsiella pneumoniae in older women of postmenopausal statuses. In addition, menopausal-specific microbial markers could exhibit excellent discriminatory ability in distinguishing breast cancer patients from controls. Finally, the functional pathways differed between breast cancer patients and controls. Our findings provide the first evidence that the gut microbiota in premenopausal breast cancer patients differs from that in postmenopausal breast cancer patients and shed light on menopausal-specific microbial markers for diagnosis and investigation, ultimately providing a noninvasive approach for breast cancer detection and a novel strategy for preventing premenopausal breast cancer. Women developing breast cancer before the menopause have less diverse gut microbe populations than their healthy peers, and significantly different gut microbial profiles than postmenopausal breast cancer patients. There is increasing evidence of a link between gut microbes and breast cancer, but most studies have focused on women after the menopause. The incidence of breast cancer in premenopausal women is increasing, especially in Asia. Researchers in Taiwan led by Chih-Po Chiang at Kaohsiung Medical University Hospital compared gut microbial populations in 267 breast cancer patients at different menopausal stages to matched controls. The results suggest that gut microbe profiling might offer a novel and noninvasive method for diagnosing and monitoring breast cancer. It may also lead to new strategies for prevention and treatment, as evidence emerges of a link between gut microbes and cancer.