GATA-3 (GATA binding protein 3) is a
member of the GATA family of transcription factors. This 50 kDa nuclear protein
regulates the development and subsequent maintenance of multiple tissues. GATA-3
orchestrates gene expression profiles during embryogenesis of a variety of human
tissues, including hematopoietic cells, skin, kidney, mammary gland, and the
central nervous system. Among several other roles, GATA-3 has recently been
identified as a key player of luminal cell differentiation in the mammary gland.
GATA-3 appears to control a set of genes involved in the differentiation and
proliferation of breast cancer. The expression of GATA-3 has a strong
association with the expression of estrogen receptor-alpha (ER) in breast
cancer, and there is mounting evidence that GATA-3 can be used as a clinical
marker to determine response to hormonal therapy and to refine the prognosis of
breast cancer patients. GATA-3 has also been shown to be a novel marker for
bladder cancer. In one study, GATA-3 stained 67% (grade 3) of 308 urothelial
carcinomas, but was negative for all prostate or renal
carcinomas.