[1151] Utility of LIN28 To Diagnose Primitive Ovarian Germ Cell Tumors.

Debin Xue, Yan Peng, Fenghua Wang, Allan Robert, Dengfeng Cao. Hangzhou Hospital of Chinese Traditional Medicine, Hangzhou, China; University of Texas-Southwestern Medical Center, Dallas; Guangzhou Children and Women's Medical Center, China; University of Florida, Gainesville; Washington University School of Medicine, St. Louis

Background: Ovarian primitive germ cell tumors (GCTs) include gonadoblastoma, dysgerminoma, embryonal carcinoma (EC), yolk sac tumor (YST), and mixed GCT. Sometimes morphologically they pose diagnostic difficulty and require immunohistochemical study. In this study we investigated the diagnostic utility of RNA-binding protein LIN28 in these tumors.
Design: Immunohistochemical staining of LIN28 was performed in 68 primary ovarian primitive GCTs [4 gonadoblastomas, 30 dysgerminomas (pure 24 pure, 4 as a component in mixed GCTs, 2 arising in association with gonadoblastoma), 6 ECs (all as a component in mixed GCTs), and 40 YSTs (20 pure, 20 as a component of mixed GCTs)] and 11 metastatic ones (9 dysgerminomas, 1 EC, and 1 YST). For comparison, 14 immature teratomas, 17 mature teratomas, 5 primary carcinoid tumors, 2 strumal carcinoids, 2 struma ovarii, and 2 squamous cell carcinomas arising in association with dermoid cysts were also stained with LIN28. To delineate LIN28 specificity in ovarian tumors, LIN28 staining was performed in 119 ovarian non-GCTs including 37 clear cell carcinomas, 11 endometrioid carcinomas, 20 high grade and 2 low grade serous carcinomas, 12 mucinous carcinomas, 2 transitional cell carcinomas, 4 small cell carcinomas (1 pulmonary-type, 3 small cell hypercalcemic type), 8 Sertoli-Leydig cell tumors, 7 steroid cell tumors, 10 adult granulosa cell tumors, 8 juvenile granulosa cell tumors, 5 fibrothecomas, and 3 benign Brenner tumors. The percentage of tumor cells stained (cytoplasmic staining) was scored as 0, 1+ (1-30% cells), 2+ (31-60%), 3+ (61-90%), and 4+ (>90%).
Results: Strong 4+ Lin28 staining was seen in 4/4 (100%) gonadoblastomas, 7/7 (100%) embryonal carcinomas (ECs), and 41/41 (100%) yolk sac tumors (YSTs). Among 39 dysgerminomas, 4+ staining was seen in 37 and 3+ staining in 2 (strong in 37, mixed weak and strong in 2). Twelve of 14 immature teratomas showed variable Lin28 staining (1+ to 4+) in the immature elements (weak to strong staining) whereas mature teratomas, carcinoids, strumal ovarii, and stromal carcinoids were negative. Only 5 of 117 non-GCTs (including 1/37 clear cell carcinomas) showed weak to moderate 1-2+ staining.
Conclusions: LIN28 is a highly sensitive marker for gonadoblastomas, dysgerminomas, ECs and YSTs. LIN28 can be used for their diagnosis and to distinguish them from non-GCTs.
Category: Gynecologic & Obstetrics

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 130, Tuesday Afternoon


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