by Jan Klos
Background
It is a member of GATA family and functions as a transcription factor involved in the luminal differentiation of breast epithelium, development of collecting system in kidneys, urothelium and trophoblastic differentiation as well as regulator of type 2 helper T cells.
Staining in normal tissues
Epidermal cells and epithelial cells of skin adnexa including apocrine but not eccrine sweat glands, distal convoluted tubules of kidney, parathyroid and epithelial cells in prostate after irradiation
Staining in tumors
Many epithelial neoplasms (>90% breast carcinomas, but only in 50-60% of triple negative breast carcinomas), circa 80% of urothelial carcinomas and skin carcinomas both with squamous and adnexal differentiation. Squamous cell carcinomas of internal organs show low frequency of positive staining (10-20%). More than 90% yolk sac tumor, choriocarcinoma, paraganglioma/pheochromocytoma, neuroblastoma are also positive. Around 50% of positive cases of epithelial-myoepithelial tumors, mesotheliomas and renal cell carcinomas (mainly fumarate hydratase deficient and chromophobe type). Other types of renal cell carcinoma including translocation carcinomas are in most cases negative. Low frequency of positive tumors (0- 10%) is reported in adenocarcinomas of the colon, endometrium, lung, stomach, prostate, pancreas, thyroid and ovary. Endocrine tumors, melanomas, small cell carcinomas are usually negative. The majority of nonepithelial tumors is negative except Ewing sarcoma/PNET, epithelioid sarcoma, angiosarcoma, leiomyosarcoma, MPNST which are positive in 10-20%. Around 30% of T-cell malignant lymphomas are positive.
Staining pattern
Nuclear
Control tissue
Kidney and tonsil.
Application
- Confirming origin of breast carcinoma.
- Excellent widely available positive (90%) marker for paraganglioma/pheochromocytoma in differential diagnosis against NET (negative)
- Considered the best overall positive marker for mesonephric and mesonephric-like carcinomas,
- Positive in substantial number of uterine carcinosarcomas (20%)
- Due to the increasing number of tumors found to express GATA3, immunohistochemical staining with additional markers is necessary to determine the etiology of metastatic lesions of unknown primary