[1213] IMP2, an Adjunct Marker That Differentiates Endometrial Serous from Endometrioid Carcinomas

L Zhang, Y Liu, D Lu. University of Massachusetts, Worcester, MA

Background: Differential diagnosis of endometrial serous from endometrioid carcinoma can be difficult especially when the endometrioid carcinoma is poorly differentiated. Accurate diagnosis however is important since their clinical course can be different and serous carcinoma may receive chemotherapy in addition. Biomarker p53, has shown to be very helpful. Here we present data of a new biomarker, IMP2, and its immunohistochemical stain for such differential diagnosis. IMP2, insulin-like growth factor II (IGF-II) mRNA-binding protein 2, is a member of family of three components, IMP1, 2, and 3. In this article, we demonstrate that IMP2 staining is always diffuse and strong in serous carcinomas, but negative, or focal in endometrioid carcinomas.
Design: The total 320 cases are selected from the specimen database at Department of Pathology, University of Massachusetts between 1997 and 2002, including benign endometrium (n-93), endometrioid carcinoma (n=178), serous carcinoma (n=27), and mixed endometrioid and serous carcinoma (n=22). The pure endometrioid carcinomas are divided into FIGO grade 1 (n=89), grade 2 (n=57), and grade 3 (n=32). For the study, the conventional H&E and IMP2 immunohistochemical stains are performed on consecutive tissue sections. The staining method is those used routinely in our lab and published elsewhere. Positive staining was defined as dark brown cytoplasmic staining pattern. Scant fine granular background staining, or no staining at all was considered negative.
Results: 1. IMP2 immunohistochemical stains of benign, endometrioid and serous carcinomas:

2. IMP2 staining differentiates serous from endometrioid carcinomas:

Conclusions: Our study indicates serous carcinomas are diffusely and strongly IMP2 positive. Endometrioid carcinomas however are always partially positive or negative. IMP2 staining pattern therefore can differentiate these two carcinomas.
Category: Gynecologic & Obstetrics

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 134, Wednesday Morning


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