In line with our results, it has been reported that gut microbes can metabolize cholesterol to produce 27-hydroxycholesterol, and the latter had been reported to promote the growth and metastasis of estrogen receptor-positive breast cancer (44, 45); taurine could be converted to hydrogen sulfide, which is a genotoxin that initiates colon cancer (46). This evidence concerns the gene ESR1 and breast carcinoma.