[1267] BAF250a (ARID1A) Combined with HNF-1b, ER and P53 Can Distinguish between Ovarian Clear Cell Carcinoma and Papillary Serous Carcinoma

Wenbin Xiao, Amad Awadallah, Wei Xin. University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH

Background: Ovarian epithelial carcinoma consists of a heterogeneous group of different types of carcinoma. Most studies have shown that clear cell carcinoma (CCC) and endometrioid adenocarcinoma might have similar genetic pathway and more commonly associated with endometriosis, while high grade papillary serous carcinoma (PSC) has a different tumorogenesis pathway with common P53 mutation. However, morphologically, high grade clear cell carcinoma and papillary serous carcinoma are not always readily distinguishable. Recent studies suggest that loss of expression of BAF250a, a tumor suppressor encoded by ARID1A, and up-regulation of hepatocyte nuclear factor (HNF)-1b were commonly present in CCC, but not PSC. In our study, we would like to show whether we could differentiate these 2 carcinomas by using a panel of immunohistochemical stains including BAF250a, HNF-1b, P53, estrogen receptor (ER) and progesterone receptor (PR).
Design: Formalin-fixed paraffin-embedded blocks of ovarian resection specimens were selected. Cases of CCC (n=26) and high grade PSC (n=24) were selected. Immunohistochemical staining for BAF250a, HNF-1b, P53, ER and PR was performed by our diagnostic lab.
Results: BAF250a, HNF-1b, P53 and ER all have different expression patterns between CCC and PSC (P<0.01), as shown in table below. Most CCCs are negative for BAF250a, ER, P53 and positive for HNF-1b, while PSC are positive for BAF250a, ER, P53 and negative for HNF-1b.

Table 1 Immunoprofiles of ovarian CCC versus PSC
CCC (N=26)42.3% (11/26)92.3% (24/26)7.7% (2/26)7.7%(2/26)15.4% (4/26)
PSC (N=24)100% (24/24)*4.2% (1/24)*91.8% (22/24)*62.5% (15/24)*16.7% (4/24)
* p<0.001 by Fisher's exact test

Conclusions: Our data support that ARIDA and HNF-1b involves ovarian CCC carcinogenesis but not in PSC. PSC and CCC are two biologically different carcinoma types and can be readily differentiated by a panel of immunohistochemical stains of BAF250a, HNF-1b, P53 and ER in morphologically challenged cases.
Category: Gynecologic & Obstetrics

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 148, Tuesday Afternoon


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