Table 1.
Summary of studies investigating the alteration of breast tissue microbiome in breast cancer.
| Sample Type and Size | Method | Variable Region | Changes to the Microbiome | Ref. | |||||
|---|---|---|---|---|---|---|---|---|---|
| Healthy | Benign | Cancer | Adjacent | Healthy Patients | Cancer Patients | Adjacent | |||
| 20 | 20 | NGS | V4 | ↑ Methylobacterium radiotolerans | ↑ Sphingomonas yanoikuyae | [2] | |||
| 24 | 17 | 22 | NGS | V3–V4 | ↓ Methylobacterium | [34] | |||
| 23 | 13 | 45 | NGS | V6 | ↑ Prevotella, Lactococcus, Streptococcus, Corynebacterium, and Micrococcus | ↑ Bacillus, Staphylococcus, Enterobacteriaceae, Comamondaceae, and Bacteroidetes. | [20] | ||
| 668 | 72 | NGS | V3–V5 | ↑ Mycobacterium fortuitum and Mycobacterium phlei | [46] | ||||
| 5, Canadians | 11 | 27 | NGS | V6 | The most abundant taxa in the Canadian samples were: Bacillus (11.4%), Acinetobacter (10.0%), Enterobacteriaceae (8.3%), Pseudomonas (6.5%), Staphylococcus (6.5%), Propionibacterium (5.8%), Comamonadaceae (5.7%), Gammaproteobacteria (5.0%), and Prevotella (5.0%). | [48] | |||
| 5, Irish | 33 | The most abundant taxa in the Irish samples were: Enterobacteriaceae (30.8%), Staphylococcus (12.7%), Listeria welshimeri (12.1%), Propionibacterium (10.1%), and Pseudomonas (5.3%). ↑ Escherichia coli |
[48] | ||||||
| 20 | 50, BRER 34, BRHR 24, BRTP 40, BRTN |
PathChip array | Unique and common microbial signatures in the major breast cancer types are summarized in Table 1 in (51) All four breast cancer types had dominant signatures for Proteobacteria followed by Firmicutes. Actinomyces signatures were also detected in each breast cancer types. |
[49] | |||||
| 9, CNB 7, SEB 3, Both |
9, CNB 7, SEB 3, Both |
NGS | V2–V4 V6–V9 |
Proteobacteria are the most abundant phylum followed by Firmicutes, Actinobacteria, and Bacteroidetes. The presence of the genus Ralstonia is associated with breast tissue. The relative abundance of Methylobacterium was different in certain patients. |
[45] | ||||
NGS: Next-generation sequencing, qPCR: quantitative Polymerase chain reaction, BRER: endocrine receptor (estrogen or progesterone receptor) positive, BRHR: human epidermal growth factor receptor 2 (HER2) positive, BRTP: triple positive (estrogen, progesterone, and HER2 receptor-positive), BRTN: triple-negative (absence of estrogen, progesterone, and HER2 receptors), CNBs: core needle biopsies, SEBs: surgical excision biopsies. Up and down arrows refer to up- and down-regulated bacteria, respectively.