The Intestinal Microbiome and Estrogen Receptor-Positive Female Breast Cancer.
Level 5 - mechanism / opinion, no new human data
Narrative review detailing theoretical and mechanistic concepts without primary data or systematic synthesis
PubMed 27107051 · doi:10.1093/jnci/djw029
What was done
This narrative review synthesizes concepts regarding how the human gastrointestinal microbiome—specifically the "estrobolome," defined as the collective enteric bacterial genes capable of metabolizing estrogens—may influence the risk of developing postmenopausal estrogen receptor-positive (ER+) female breast cancer.
What was found
The abstract reports no clinical trial results or empirical effect estimates. It notes the biological context that the human gastrointestinal tract harbors up to 10(11) bacterial cells per gram of luminal content and describes how alterations in the composition and functional capacity of the estrobolome could modify systemic estrogen levels and cancer risk.
Why it matters
The paper outlines a mechanistic framework linking gut microbial metabolism to circulating estrogen levels, framing the estrobolome as a potential source of risk biomarkers and a target for future preventative interventions.
Limits
This publication is a narrative review with no original clinical or experimental data reported in the abstract. It provides mechanistic hypotheses rather than validated diagnostic or therapeutic outcomes, and it lacks quantitative syntheses or systematic study pooling.
Cited by
- supports Gut bacterial beta-glucuronidase deconjugates estrogen metabolites, and gut dysbiosis can cause estrogen recirculation and elevated estradiol levels.