Transcription factor gata-binding protein 3 (GATA3) has a quite complex function in micro-environmental re-modeling and metastasis inhibition through its regulation of miR-29b expression, and down-regulation of miR-29b in GATA3-expressing luminal breast cancers resulted in metastatic development and a mesenchymal phenotype in cancer cells. This evidence concerns the gene GATA3 and breast cancer.