[216] Immunohistochemical Evaluation of GATA-3 Expression in ER-Negative Breast Carcinomas

Haiyan Liu, Jianhui Shi, Jeffrey Prichard, Yun Gong, Fan Lin. Geisinger Medical Center, Danville, PA; University of Texas MD Anderson Cancer Center, Houston, TX

Background: Currently, estrogen receptor (ER), GCDFP-15 and mammaglobin are the most commonly used immunomarkers for identifying breast primary in tumors of unknown origin. The reported sensitivities for GCDFP-15 and mammaglobin are in the ranges of 35-55% and 65-70%, respectively. Our un-published data are even lower, 35% for GCDFP-15 and 50% for mammaglobin, which are similar to the reports by Bhargava et al and Lewis et al. Metastatic breast carcinomas (BCA) are likely high grade with ER-negative status. It is practical to find a sensitive and breast organ specific immunomarker. GATA-3 is a sensitive and specific marker for breast and urothelial carcinomas, as reported in our previous study (Liu H, et al. AJCP. 2012;138:57-64). However, the reactivity of GATA-3 in ER-negative breast carcinomas (BCA) has not been reported. In the current study, we conducted immunohistochemical analysis of GATA-3 expression in 96 cases of ER-negative BCA, including 49 tissue microarray (TMA) and 47 core needle biopsy (CNB) cases.
Design: Immunohistochemical evaluation of the expression of GATA-3 (Santa Cruz Biotech Inc, Cat. No. GATA3 [HG3-31]:sc-268) on 96 cases of ER-negative BCA using TMA sections (49 cases) and CNB specimens (47 cases) was conducted. The results were recorded.
Results: GATA-3 expression in 96 cases of ER-negative BCA is recorded in Table 1. Overall, 59% of TMA and 79% of CNB cases showed nuclear staining for GATA-3, with majority (73%) being strong (S) and diffuse (4 or 3+).

Table 1. GATA-3 Expression in 96 Cases of ER Negative Breast Carcinomas
Tumor TypeGATA-3 Expression, TMAGATA-3 Expression, Core Biopsy
IDC, G22113628788
IDC, G3221568302480
IDC, HG, Metaplastic1004125
IDC, HG, Medullary Features20011100
IDC, Apocrine Features215044100
N=number of cases; Pos.=positive; IDC=Invasive ductal carcinoma

Conclusions: GATA-3 is expressed in majority (66/96, 69%) of the ER-negative BCA, which may serve as a sensitive and breast organ specific immunomarker in the workup of tumors of unknown origin, with the exception of urothelial carcinomas as reported in our previous study, which has a positive rate of 86% (62/72). GATA-3 expression is less or none in carcinomas with medullary features or metaplastic BCA in the few cases included in this study, which needs to be validated in larger studies.
Category: Breast

Monday, March 4, 2013 11:45 AM

Proffered Papers: Section B, Monday Morning


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