[1137] Her2-Neu Over-Expression in Serous and Clear Cell Endometrial Carcinoma.

Rebecca G Stovel, Reda S Saad, Nadia Ismiil, Zeina Ghorab, Valerie Dube, Mahmoud A Khalifa, Sharon Nofech-Mozes. Sunnybrook Health Sciences Centre, Toronto, ON, Canada

Background: Type II endometrial carcinoma includes high grade, non-estrogen driven tumors with a molecular pathway distinct from Type I (endometrioid type). Histologically, it consists of serous and clear cell carcinomas with some morphologic overlap. Although Type II represents 9-14% of endometrial cancers it is associated with aggressive clinical course and accounts for 48% of deaths. Her2/neu oncoprotein is an established target for therapy in breast cancer and has an emerging role in the treatment of gastric cancer. The aim of this study is to determine the proportion of Her-2/neu overexpression in Type II endometrial carcinoma and the association between this receptor and stage at presentation.
Design: We identified a set of 36 clear cell endometrial carcinomas and 34 serous endometrial carcinomas accessioned from 2000-10. Cases were reviewed independently by two gynecological pathologists. Her-2/neu oncoprotein over-expression was determined by immunohistochemistry. Only a strong and complete membranous staining pattern was considered positive. Clinical information was retrieved from the electronic medical records.
Results: Overall Her-2/neu overexpression was found in 11/70 (15.7%) endometrial Type II cases; 6/34 (18%) of the serous carcinomas, and 5/36 (14%) of clear cell carcinomas. Typically the expression was focal, in less than half of the tumor cells. 61/ 70 patients underwent full surgical staging. In the remaining 9 cases, staging was based on a more limited surgical procedure. Of the fully staged patients, 12 had extrauterine involvement at time of surgery and 49 did not. Her-2/neu expression was not associated with extrauterine disease (p >0.05).
Conclusions: Our study demonstrates that Her2/neu oncoprotein is overexpressed in about 16% of Type II endometrial cancer. The proportion of this subset is similar to that observed in breast cancer. This observation opens the door for inclusion of novel targeted therapies directed against Her2/neu in clinical trials for aggressive type of endometrial cancer.
Category: Gynecologic & Obstetrics

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 168, Wednesday Afternoon

 

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