Endocrine-targeting therapies shift the breast microbiome to reduce estrogen receptor-α breast cancer risk.

ABSTRACT: Studies indicate that breast tissue has a distinct modifiable microbiome population. We demonstrate that endocrine-targeting therapies, such as tamoxifen, reshape the non-cancerous breast microbiome to influence tissue metabolism and reduce tumorigenesis. Using 16S sequencing, we found that tamoxifen alters β-diversity and increases Firmicutes abundance, including Lactobacillus spp., in mammary glands (MGs) of mice and non-human primates. Immunohistochemistry showed that lipoteichoic acid (LTA)-positive bacteria were elevated in tamoxifen-treated breast tissue. In B6.MMTV-PyMT mice, intra-nipple probiotic bacteria injections reduced tumorigenesis, altered metabolic gene expression, and decreased tumor proliferation. Probiotic-conditioned media selectively reduced viability in estrogen rece

SUBMITTER: Arnone AA 

PROVIDER: S-EPMC11866439 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature