[1086] ARID1A Gene Expression in High-Grade Endometrial Carcinomas

Ghassan Allo, Helen Mackay, Marjan Rouzbahman, Patricia Shaw, Marcus Bernardini, Blaise A Clarke. University of Toronto, University Health Network, Toronto, ON, Canada

Background: ARID1A is a putative tumour suppressor gene in endometriosis-associated ovarian carcinomas. Its protein product, BAF250a, is a key component of the multi-protein SWI/SNF chromatin remodelling complex, related to multiple cellular functions including DNA repair. Loss of BAF250a expression has recently been described in 96 of 332 endometrial carcinomas of different types. In this study, we analyze expression of BAF250a in high-grade endometrial carcinomas, and correlate it with patients' clinical parameters.
Design: Annotated double-cored tissue microarrays of 216 primary endometrial carcinoma cases were immunohistochemically stained for ARID1A gene product using BAF250a mouse clone 3H2 antibody (Abgent, San Diego, CA, USA). Statistical analyses were performed using IBM SPSS Statistics v.19.0.0.
Results: Tumour was present in 210 of 216 stained cases, of which 61 cases (29.01%) showed loss of BAF250a expression, including 47.42% high-grade endometrioid carcinomas (n=46/97), 10.3% serous carcinomas (n=10/97), and 31.3% uterine clear cell carcinomas (n=5/16). Mean age of patients with BAF250a expression loss was slightly lower than that of patients with retained protein expression (62.36 ±11.68 vs. 68.64±9.88 years; p<0.001). In addition, lymph node metastasis was more likely to occur in high-grade endometrioid endometrial carcinomas with BAF250a loss than those with retained expression (33.3% vs. 9.7%, respectively; p=0.027, OR=.214, 95%CI [0.051-0.9]). There was no significant correlation between BAF250a expression loss and the tumour T-stage.
Conclusions: This study confirms the loss of expression of ARID1A gene product in endometrial carcinomas in comparable proportion to what is previously reported. In addition, we show a potential correlation of gene expression loss and development of lymph node metastasis in high-grade endometrioid endometrial carcinomas.
Category: Gynecologic & Obstetrics

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 147, Wednesday Morning


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