September 22, 2023

GATA-3 (GATA binding protein 3) is a transcription factor that plays an important role in the development and differentiation of various cells within the body. It is part of the GATA family of transcription factors, which bind to specific DNA sequences in the promoter regions of target genes to regulate their expression. GATA-3 is particularly important in the development of T cells and is a key regulator in the immune system, influencing the development of the Th2 (T helper 2) cell lineage, which is involved in the immune response to parasites and allergic reactions.

In pathology and diagnostic immunohistochemistry (IHC), GATA-3 expression is used as a biomarker for certain types of cancers. It is notably expressed in:

  • Breast cancers: GATA-3 is highly expressed in most types of breast cancer, especially those that are estrogen receptor-positive (ER+), making it a useful marker in the diagnosis and potentially in understanding the prognosis of breast cancer.
  • Urothelial carcinoma: GATA-3 is also expressed in the majority of urothelial carcinomas (originating from the urinary tract’s lining), aiding in the diagnosis of these tumors.
  • Some squamous cell carcinomas and various other carcinomas may also show GATA-3 expression.

The detection of GATA-3 expression can help pathologists differentiate between various tumor types and can support the identification of the primary site of tumors, especially in cases of metastatic cancer where the origin is unknown.

What types of cells normally express GATA-3?

GATA-3 is normally expressed in a variety of cell types and tissues, reflecting its importance in different physiological processes, including development and immune function. The primary cells and tissues that express GATA-3 include:

  • T cells: GATA-3 is critically involved in the differentiation and function of T cells, particularly in the development of Th2 (T helper type 2) cells. Th2 cells play a pivotal role in the immune response against parasites and are involved in allergic reactions. GATA-3 regulates the expression of cytokines characteristic of the Th2 response, such as IL-4, IL-5, and IL-13.
  • Epithelial cells: GATA-3 is expressed in various epithelial cells throughout the body, including the cells in the breast, kidney, and skin. In the breast, GATA-3 is important for the development of luminal epithelial cells and is a key marker used in breast cancer diagnosis.
  • Urothelial cells: GATA-3 is involved in the development and differentiation of the urothelium, the epithelial lining of the urinary bladder, and parts of the urinary tract. Its expression in urothelial cells makes it a useful diagnostic marker for urothelial carcinoma.
  • Trophoblasts: In the placenta, GATA-3 expression is observed in trophoblasts, cells that play a key role in implantation and interaction with maternal tissues during pregnancy.
  • Central nervous system: There is evidence of GATA-3 expression in certain parts of the brain, indicating a potential role in the development and function of the central nervous system.
  • Thymus: GATA-3 is involved in the development of the thymus and the maturation of thymocytes, precursors to T cells.

Examples of tumours that express GATA-3

GATA-3 is expressed by tumors that arise in the skin, salivary glands, female reproductive tract, kidney, and urinary tract. Some tumours that arise from the peripheral nervous system also express this protein.

Some examples of GATA-3 expressing tumours include:

Tests performed to detect GATA-3

Pathologists test for GATA-3 expression in tissue samples primarily through immunohistochemistry (IHC), a technique that utilizes antibodies to detect specific antigens (proteins) within cells of a tissue section. Positive GATA-3 staining is typically observed as a nuclear (and sometimes cytoplasmic) expression. The intensity and distribution of staining help in the diagnosis and classification of various diseases, including identifying the origin of metastatic tumors or confirming the diagnosis of specific types of cancers, such as breast cancer and bladder cancer.


About this article

Doctors wrote this article to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report. For a complete introduction to your pathology report, read this article.

Other helpful resources

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