Collectively, these observations indicate that a decreased in the availability of Foxp3 could cause a decisive increase in Runx1 transcriptional activity, which may alter migration abilities of tumor cells by binding and regulating it's downstream target genes such as Rspo3 and Gja1. These data strongly suggest that Runx1/Foxp3 interaction could be a new mechanism of gene expression regulation during breast cancer development. This evidence concerns the gene GJA1 and breast carcinoma.