[1089] PLZF Immunostaining Distinguishes Low-Grade and High-Grade Ovarian Serous Tumors.

Yuxin Liu, Yayoi Kinoshita, Tamara L Kalir, David E Burstein. Mount Sinai School of Medicine, New York, NY

Background: PLZF (Promyelocytic Leukemia Zinc Finger), a zinc-finger transcriptional repressor plays an important role in cell cycle regulation. We investigated the PLZF expression in ovarian benign epithelium, borderline tumors with or without micropapillary foci, and in low-grade, and high-grade serous carcinoma.
Design: 55 routinely processed specimens, comprising benign ovary (n=10), serous cystadenoma or adenofibroma (n=10), serous borderline tumor (n=10), serous borderline tumor with micropapillary foci (n=10), high grade serous carcinoma (n=10), and low grade serous carcinoma (n=5) were subjected to citrate-based Ag retrieval followed by exposure to streptavidin-biotin reagents and diaminobenzidine.
Results: In normal ovarian surface, PLZF staining was nuclear and was positive in 80-100% of epithelial lining cells. Nuclear staining was also seen in serous cystadenofibroma, in 90-100% of epthelial cells. In contrast, serous borderline tumors displayed cytoplasmic and perinuclear rather than nuclear staining, with about 10-20% of tumor cells staining. In micropapillary foci, cytoplasmic PLZF staining further decreased to 3-5 % epithelial cells on the long slender micropapillae (Fig. 1 A – F).

Staining of low-grade serous carcinoma was easily distinguished from high grade serous carcinoma: the former displayed cytoplasmic PLZF expression in 5-10% of tumor cells, whereas the latter were completely non-staining (Fig.2 A-D).

Conclusions: PLZF immunostaining distinguished ovarian normal, low grade neoplastic and high grade malignant epithelia. Our findings are consistent with basic studies that have defined a mechanism of nuclear export of PLZF corresponding to de-repression of cell proliferation. These findings define a new means of distinguishing ovarian serous tumors. Downregulation of PLZF may contribute to uncontrolled serous epithelial cells proliferation; therefore it may play an important role in ovarian serous tumor pathogenesis.
Category: Gynecologic & Obstetrics

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 101, Tuesday Afternoon


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