[1137] Coordinate Patterns of ER, PR and WT1 Expression Are Useful in the Distinction of Ovarian from Endometrial Serous Carcinomas and Significantly Outperform Individual Markers

Oluwole Fadare, Samuel James, Mohamed M Desouki, Dineo Khabele. Vanderbilt University, Nashville, TN

Background: The pathologic distinction of ovarian serous carcinoma (OSC) from endometrial serous carcinomas (ESC) is important for accurate tumor staging, epidemiological data extracted therefrom, the reporting of probable primary sites in biopsies or cytologic preparations, and occasionally, chemotherapeutic choices. The purpose of this study is to assess whether composite or coordinate protein expression patterns of estrogen receptor (ER), progesterone receptor (PR) and Wilms tumor suppressor gene (WT1) can significantly distinguish between ESC and OSC.
Design: Imunohistochemical analyses were performed on whole tissue sections from 22 uterus-confined (FIGO stage I/II) ESC and on a TMA of 140 high-grade ovarian serous carcinomas of various stages, using antibodies to ER, PR, and WT1.
Results: ER, PR and WT1 expression was present in 37%, 49% and 81% of OSC respectively, but these markers were also expressed in 18%, 27% & 36% of ESC. The ER+/PR+/WT1+ coordinate profile was identified in 33.6% of OSC but in 0% of ESC (p=0.0006), resulting in a calculated sensitivity and specificity of this profile for OSC of 33.6% and 100% respectively. By contrast, the ER-/PR-/WT1- profile was identified in 41% of ESC but in only 6.4% of OSC (p=0.0001) resulting in a calculated sensitivity and specificity of this profile for ESC of 50% and 94% respectively,

Coordinate Immunophenotypic Patterns
ImmunophenotypesESC. No of cases (%)OSC. No of cases (%)p value (Fisher's Exact test)
ER+/PR+/WT1+0(0)47 (33.6)0.0006

Conclusions: Each of the 3 markers was significantly more frequently expressed in OSC than ESC, which affirms the differential localization of these antigens in OSC and ESC, their shared morphologic profile notwithstanding. However, none of them should be used in isolation for distinguishing OSC from ESC, as they each lack discriminatory power when so utilized due to their suboptimal specificity. Furthermore, the use of single markers has a substantial probability of generating erroneous results regarding the site of origin. In the differential diagnosis between OSC and ESC, positivity for all 3 markers strongly favors an extrauterine origin. Negativity for all 3 markers, although supportive of an endometrial origin, is not entirely conclusive in either direction. Composite profiles, in general, have a high specificity but low sensitivity in this differential diagnosis.
Category: Gynecologic & Obstetrics

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 117, Tuesday Morning


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