[1126] Expression of SOX17: A Novel Marker in Ovarian Germ Cell Tumors

AM Leathersich, D Cao. Washington University School of Medicine, St. Louis, MO

Background: Ovarian germ cell tumors (GCT) are rare and range from benign to malignant lesions. A novel marker, SOX17, has recently been shown to distinguish seminoma from embryonal carcinoma in the testis. The goal of this study is to investigate the diagnostic utility of the transcription factor SOX17 in ovarian GCT's and non-GCT's.
Design: One hundred and three ovarian GCT's were retrieved including 27 dysgerminomas, 35 yolk sac tumors (YST), 5 Embryonal carcinomas (EC), 13 immature teratomas (IM), 8 mature teratomas (MT), 5 gonadoblastomas (GB), 6 combined carcinoid and teratoma, 1 carcinoid, and 2 struma ovarii. We also stained 72 primary non-GCT's of the ovary including 9 endometrioid carcinomas, 11 high grade serous carcinomas, 9 mucinous carcinomas, 1 transitional cell carcinoma (TCC), 13 clear cell carcinomas, 2 benign Brenner tumors, 2 neuroendocrine tumors, 7 juvenile granulosa cell tumors (GCT), 6 adult GCTs, 7 steroid cell tumors, 2 Sertoli-Leydig cell tumors, and 3 fibrothecomas. Unstained slides generated from 1 to 2 paraffin embedded tissue blocks per case were stained with SOX17 monoclonal antibody. Only nuclear staining was counted as positive. The percentage of tumor cells stained was scored semiquantitatively as 0 (no tumor cells staining), 1+(<30% cells), 2+(31-60% cells), 3+(61-90% cells), 4+(>90% cells).
Results: Twenty-five out of 26 (96%) dysgerminomas and 28 of 35 (80%) YST showed 3+ to 4+ (>60%) nuclear staining for SOX17. 100% of GB cases showed staining. IT was negative in 62% of cases. EC and MT were negative for SOX17.

Sox17 Staining in Ovarian Germ Cell Tumors
Tumor Type01+2+3+4+
Immature Teratoma84100
Mature Teratoma80000
Carcinoid and Teratoma70000
Struma Ovarii20000

All cases of endometrioid, high grade serous, and clear cell carcinoma showed at least 1+ nuclear staining, with 3+ to 4+ staining in 67, 55, and 38% of cases, respectively. Juvenile GCT, steroid cell tumor, Sertoli-Leydig cell tumor, fibrothecoma, choriocarcinoma, struma ovarii, and benign Brenner tumors showed no nuclear staining in 100% of the cases. One case in six of adult GCT showed 3+ staining, the remaining cases showed no nuclear staining. The TCC showed 4+ staining.
Conclusions: SOX17 is a novel marker that can distinguish dysgerminomas and YST from EC. SOX17 does not show nuclear staining in sex-cord stromal tumors and most teratomas.
Category: Gynecologic & Obstetrics

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 171, Wednesday Afternoon


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