GATA3 is a zinc finger transcription factor that was first recognized as a possible determinant of T cell development. Later studies demonstrated that it is expressed in trophoblast giant cells and regulates trophoblast-specific genes during development. Specifically, GATA3 is selectively expressed in the trophectoderm of the peri-implantation embryo and regulates CDX2, which is required for the transcriptional repression of the POU5F1/Oct4 and NANOG genes and is thus essential for the segregation of the inner cell mass and trophectoderm at the blastocyst stage. Decreased or null-expression expression of GATA3 has also been suggested to play a major role in the development and progression of luminal breast cancer.
