H2BC21 and breast cancer: The expression of 221 genes was positively associated with the higher activity of Lactobacillus in ER-negative (ER-/HER2 + and triple-negative types) samples (r > 0.7, p < 0.05) including breast cancer biomarker genes PLA2G2E, HIST2H2BE, CRKL, and CCND1 (Table 3) and the expression of same genes was negatively correlated with the relative activity of Bacteroides (Table 3).