[220] Expression of Estrogen Receptor and BRCA1 in Male and Female Breast Cancer

TS Kraus, C Cohen. Emory University, Atlanta, GA

Background: There has been recent interest in the role of estrogen receptor (ER) expression in breast carcinomas. A previous report showed frequent ER expression in male breast carcinomas (MBC). Data comparing ER expression in MBC and female breast carcinomas (FBC) is limited. ER expression has also been shown in triple negative (ER-, PR-, HER2-), BRCA1-mutation-associated FBC. In this study, we compared expression of BRCA1, ER, ER, progesterone receptor (PR), androgen receptor (AR) and HER2 in MBC and FBC, and examined the possible relationship between ER and BRCA1.
Design: Immunohistochemical stains for BRCA1, ER, ER, PR, AR, and HER2 were performed on tissue microarrays representing 32 MBC (four 1.0 mm cores per case) and 82 FBC (two 1.0 mm cores per case). Absence of nuclear staining for BRCA1 suggested presence of a BRCA1 mutation. A positive reaction for the steroid receptor stains was defined as nuclear staining present in at least 10% of tumor cells. HER2 was scored according to CAP guidelines. HER2 FISH results were obtained in cases with equivocal and positive HER2 staining.
Results:

MBCFBCp-value
BRCA1 (-)0/28 (0%)2/77 (2.6%)1
ER24/25 (96%)64/66 (97%)1
ER23/27 (85.2%)49/73 (67.1%)0.085
PR14/27 (51.9%)40/76 (63.9%)1
AR20/27 (74.1%)46/72 (63.9%)0.473
HER26/26 (23.1%)14/63 (22.2%)1


No BRCA1 mutations were identified in the MBC cases. Both triple-negative MBC were ER-positive. BRCA1 staining was absent in two of 12 triple-negative FBC. ER staining was present in both cases. The ER-negative MBC and one of two ER-negative FBC were positive for ER.
Conclusions: In our population, the expression of all studied markers, including ER, was similar in MBC and FBC. The expression of ER in triple-negative tumors with absent BRCA1 staining in FBC is confirmed. BRCA1 mutation was not noted in any MBC, possibly due to the small sample size.
Category: Breast

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 35, Monday Morning

 

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