[1179] FOXL2 Molecular Testing in the Diagnosis of Ovarian Neoplasms

Stefan Kommoss, Michael Anglesio, Winnie Yang, Wilson Luong, Julie Lorette, Lynda Bell, Sylvia Lee, Blake Gilks, David Huntsman. University of British Columbia, Vancouver, BC, Canada; British Columbia Cancer Agency, Vancouver, BC, Canada

Background: Recently a single, recurrent somatic mutation (402C→G) in FOXL2 was identified in almost all adult-type granulosa cell tumors (aGCT) but not other ovarian neoplasms. The histopathological features of aGCT can be mimicked by a variety of other tumors, making diagnosis of aGCT challenging. It has been suggested that molecular testing for FOXL2 mutation might be a useful tool in the diagnosis of aGCT. The aim of this study is to demonstrate how testing for the FOXL2 mutation can be used in a gynecological pathology consultation service.
Design: Immunohistochemistry (IHC) for FOXL2 was done using an anti-FOXL2 polyclonal antiserum. If IHC was positive, the FOXL2 mutation status was subsequently analyzed using a TaqMan PCR assay. In cases with a scattered growth pattern or minimal tumor only, laser capture of tumor cells was done prior to DNA extraction.
Results: To date, 10 problematic cases have been assessed where the differential diagnosis after the initial investigations included aGCT. The differential diagnoses included: Sertoli Leydig cell tumor (SLCT), juvenile granulosa cell tumor (jGCT), endometrial stromal sarcoma (ESS). and follicular cyst. In all cases FOXL2 IHC was positive, however in only two samples was the FOXL2 mutation detected, thus confirming a diagnosis of aGCT in these 2 cases.
Conclusions: The analysis of the FOXL2 mutational status in clinical samples was a useful diagnostic tool in situations where the differential diagnosis was between aGCT and SLCT, jGCT, ESS and follicular cyst. The informative value of this test is limited to the question of whether a given tumor is an adult type granulosa cell tumor or not, but it is highly specific in this context.
Category: Gynecologic & Obstetrics

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 201, Tuesday Morning


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