Supplementary Material for: GATA3 Expression in Human Tumors: A Tissue Microarray Study on 16,557 Tumors

<b><i>Introduction:</i></b> GATA3 is a transcription factor involved in epithelial cell differentiation. GATA3 immunostaining is used as a diagnostic marker for breast and urothelial cancer but can also occur in other neoplasms. <b><i>Methods:</i></b> To evaluate GATA3 in normal and tumor tissues, a tissue microarray containing 16,557 samples from 131 different tumor types and subtypes and 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry. <b><i>Results:</i></b> GATA3 positivity was found in 69 different tumor types including 23 types (18%) with at least one strongly positive tumor. Highest positivity rates occurred in noninvasive papillary urothelial carcinoma (92–99%), lobular carcinoma (98%), carcinoma of no special type of the breast (92%), basal cell carcinoma of the skin (97%), invasive urothelial carcinoma (73%), T-cell lymphoma (23%), adenocarcinoma of the salivary gland (16%), squamous cell carcinoma of the skin (16%), and colorectal neuroendocrine carcinoma (12%). In breast cancer, low GATA3 staining was linked to high pT stage (<i>p</i> = 0.03), high BRE grade (<i>p</i> &lt; 0.0001), HER2 overexpression (<i>p</i> = 0.0085), estrogen and progesterone receptor negativity (<i>p</i> &lt; 0.0001 each), and reduced survival (<i>p</i> = 0.03). <b><i>Conclusion:</i></b> Our data demonstrate that GATA3 positivity can occur in various tumor entities. Low levels of GATA3 reflect cancer progression and poor patient prognosis in breast cancer.