[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 group	H-score 0	H-score 1-10	H-score 11-50	H-score 51-150	H-score >150	Total
ER+/HER2—	26	11	22	45	27	131
ER+/HER2+	5	2	7	2	1	17
ER—/PR—/HER2+	4	1	1	1	1	8
ER—/PR—/HER2—	25	0	1	3	0	29
Total	60	4	31	51	29	185

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 type	NYBR1 negative	NYBR1 positive	Total
Endometrial endometrioid	35	4	39
Endometrial non-endometrioid	13	3	16
Endocervical carcinoma	34	0	34
Ovarian clear cell	34	0	34
Ovarian endometrioid	3	1	4
Ovarian serous	15	0	15

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