In summary, the forest plot showed that Bifidobacterium inhibited the abundance of CD39+Tregs using the IVW method (OR = 0.785, P = .0349), CD39+Tregs were a risk factor for prostate cancer (OR = 1.015, P = .0421), and Bifidobacterium was a protective factor for prostate cancer (OR = 0.905, P = .0429) (Fig. 4). This evidence concerns the gene ENTPD1 and prostate carcinoma.