%0 Journal Article
%T Gut microbiome associations with breast cancer risk factors and tumor characteristics: a pilot study.
%A Wu AH
%A Tseng C
%A Vigen C
%A Yu Y
%A Cozen W
%A Garcia AA
%A Spicer D
%J Breast Cancer Res Treat
%V 182
%N 2
%D Jul 2020
%M 32468338
%F 4.624
%R 10.1007/s10549-020-05702-6
%X <B>OBJECTIVE: </B>To investigate the association between gut microbiome with breast tumor characteristics (receptor status, stage and grade) and known breast cancer risk factors.<BR><B>METHODS: </B>In a pilot cross-sectional study of 37 incident breast cancer patients, fecal samples collected prior to chemotherapy were analyzed by 16S ribosomal RNA (rRNA) gene-based sequencing protocol. Alpha diversity and specific taxa by tumor characteristics and breast cancer risk factors were tested by Wilcoxon rank sum test, and by differential abundance analysis, using a zero-inflated negative binomial regression model with adjustment for total counts, age and race/ethnicity.<BR><B>RESULTS: </B>There were no significant alpha diversity or phyla differences by estrogen/progesterone receptor status, tumor grade, stage, parity and body mass index. However, women with human epidermal growth factor receptor 2 positive (HER2+) (n = 12) compared to HER2- (n = 25) breast cancer showed 12-23% lower alpha diversity [number of species (OTU) p = 0.033, Shannon index p = 0.034], lower abundance of Firmicutes (p = 0.005) and higher abundance of Bacteroidetes (p = 0.089). Early menarche (ages ≤ 11) (n = 11) compared with later menarche (ages ≥ 12) (n = 26) was associated with lower OTU (p = 0.036), Chao1 index (p = 0.020) and lower abundance of Firmicutes (p = 0.048). High total body fat (TBF) (> 46%) (n = 12) compared to lower (≤ 46%) TBF was also associated with lower Chao 1 index (p = 0.011). There were other significant taxa abundance differences by HER2 status, menarche age, as well as other tumor and breast cancer risk factors.<BR><B>CONCLUSIONS: </B>Further studies are needed to identify characteristics of the human microbiome and the interrelationships between breast cancer hormone receptor status and established breast cancer risk factors.