The results showed that mice in both the negative control group and the FOXP3-MTA1 group had breast cancer metastasis to the lungs, while mice in the FOXP3 group did not show significant breast cancer metastasis to the lungs (Figure 3H), confirming that FOXP3 can inhibit the metastasis of breast cancer cells by regulating MTA1 expression in vivo. This evidence concerns the gene MTA1 and breast carcinoma.