[1307] GATA3 Immunoexpression in Salivary Gland Neoplasms

Lauren E Schwartz, William H Westra, Justin A Bishop. Johns Hopkins Hospital, Baltimore, MD

Background: GATA3 is a zinc finger transcription factor that regulates the normal development of many tissues and cell types. Recent studies have shown that immunohistochemical nuclear staining for GATA3 among tumors is almost entirely limited to carcinomas of breast and urothelial origin. However, to our knowledge salivary gland tumors have not been tested with this antibody. Given that breast tissue and salivary gland tissue share a similar embryologic origin, we sought to determine whether GATA3 staining may be seen in salivary gland neoplasms.
Design: GATA3 immunohistochemistry (clone L50-823, BioCare, Concord, CA) was performed on a diverse collection of 164 primary salivary gland neoplasms (122 on tissue microarrays and 42 on whole slides), and the staining patterns were recorded.
Results: The results are summarized in Table 1. Staining for GATA3 was observed in 81/164 (49%) of salivary gland tumors. The background benign salivary was also usually weakly positive in acini and ducts. Some staining was seen in almost every tumor type tested, but it was particularly common in tumors with an "oncocytic" histologic appearance. Notably, GATA3 was 100% sensitive for two tumors that histologically mimic breast cancer: salivary duct carcinoma (25/25) and mammary analogue secretory carcinoma (15/15). Overall, most GATA3 tumor staining was weak or moderate in intensity, though salivary duct carcinoma (17/25 or 68%) and mammary analogue secretory carcinoma (9/15 or 60%) often showed strong positivity.

Table 1
Tumor typeGATA3 staining (%)
Acinic cell carcinoma1/7 (14)
Adenocarcinoma, NOS0/2 (0)
Adenoid cystic carcinoma9/41 (22)
Epithelial-myoepithelial carcinoma1/2 (50)
Mammary analogue secretory carcinoma15/15 (100)
Mucoepidermoid carcinoma11/27 (41)
Oncocytic carcinoma1/2 (50)
Oncocytoma5/5 (100)
Pleomorphic adenoma13/34 (38)
Polymorphous low grade adenocarcinoma0/4 (0)
Salivary duct carcinoma25/25 (100)
Total81/164 (49)

Conclusions: GATA3 immunostaining is relatively common in salivary gland neoplasms. As a result, a salivary gland origin must be considered in the differential diagnosis of a GATA3-positive carcinoma of unknown primary. In addition, GATA3 immunohistochemistry cannot be used to rule out metastatic breast cancer in the setting of a salivary gland tumor that has the appearance of breast carcinoma. Finally, although GATA3 is not specific for any salivary gland tumor, strong staining may be helpful to confirm the diagnosis of salivary duct carcinoma or mammary analogue secretory carcinoma.
Category: Head & Neck

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 145, Tuesday Morning


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