[291] NYBR1 Expression in Breast and Gynecologic Tract Carcinomas.

Anna H Woodard, Jing Yu, David J Dabbs, Anca V Florea, Sushil Beriwal, Rohit Bhargava. Magee-Womens Hospital of UPMC, Pittsburgh, PA

Background: The distinction of breast carcinomas from CK7+/ER+/CK20 negative gynecologic tumors is often difficult and other immunohistochemical markers, such as mammaglobin, may be positive in both. GCDFP-15 has low sensitivity to be an effective breast marker. Vimentin stains endometrioid endometrial carcinomas, but in one third of cases may be negative or focally expressed. NYBR1 is a mammary differentiation antigen that may be helpful in these difficult cases.
Design: Tissue microarrays containing 185 primary breast carcinomas and 142 gynecologic carcinomas were stained with NYBR1 mouse monoclonal antibody (NY-BR-1#2). All tumors were semi-quantitatively scored using the H-score method where the score ranges from 0 (negative) to 300 (diffuse strong reactivity).
Results: Among primary breast carcinomas, the overall sensitivity of NYBR1 was 60% (H-score >10). Sensitivity was slightly higher for ER+ tumors: 70% (104/148).

NYBR1 expression with respect to hormone receptors and HER2 expression
Breast tumor groupH-score 0H-score 1-10H-score 11-50H-score 51-150H-score >150Total

NYBR1 expression was associated with ER expression (p <0.0001) and lower Nottingham grade (p<0.0001). Most (67%) of the Nottingham grade 3 tumors were negative for NYBR1 expression while most (63%) of the Nottingham grade 1 tumors showed moderate to strong expression (H-score >50). Endometrial tumors were rarely positive for NYBR1 and had weak expression (mean H-score 26). Endocervical tumors were almost completely negative with only negligible expression in some (H-score 1-10). Ovarian tumors were mostly negative with only one endometrioid type showing NYBR1 expression (H-score 60).

NYBR1 Expression in gynecologic tumors
Site and tumor typeNYBR1 negativeNYBR1 positiveTotal
Endometrial endometrioid35439
Endometrial non-endometrioid13316
Endocervical carcinoma34034
Ovarian clear cell34034
Ovarian endometrioid314
Ovarian serous15015
H score >10 considered as positive

Conclusions: Moderate to strong NYBR1 expression in a CK7+/ER+/CK20 negative tumor supports the diagnosis of a primary breast carcinoma rather than a gynecologic tumor. For breast carcinoma, NYBR1 is a more specific marker than mammaglobin as endometrioid tumors are only rarely (and weakly) positive with NYBR1, but mammaglobin is moderately positive in 40% of endometrioid tumors. NYBR1 expression is not useful in distinguishing between endometrial and endocervical tumors.
Category: Breast

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 40, Monday Morning


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