[1143] Immunohistochemical (IHC) Characterization of Mullerian Adenosarcomas (AS)

L Mirham, MA Khalifa, S Nofech-Mozes, N Ismiil, RS Saad, Z Ghorab, V Dube. Sunnybrook Health Sciences Centre, Toronto, Canada

Background: Mullerian AS are rare biphasic tumors composed of benign epithelium admixed with sarcomatous elements. Little is known regarding their IHC profile and its potential prognostic implication. In this study, we aim at characterizing the IHC expression of a panel of descriptive and potentially prognostic markers in AS, as well as markers linked to targeted therapies.
Design: In-house cases of AS accessioned between 1999-2008 were retrieved from the archives of Sunnybrook HSC. Slides and patients' charts were reviewed and the following data was recorded; tumor site, sarcomatous overgrowth (SO) and tumor recurrence. Original and recurrent tumors were studied using a panel of antibodies (ER, PR, CD10, p53, CD117, Her2/neu, EGFR) and IHC staining of the sarcomatous component was recorded semiquantitatively (0%; 1-25%; 26-50%; >50% of positive cells).
Results: 21 AS patients were identified (10 endometrial, 8 cervical and 3 ovarian). 4 patients had recurrrence but tissue was available for IHC study in only 3 of them (total: 24 tumors studied). SO was identified in 6 cases. IHC staining was positive at least focally (>1% of cells) in the following number of tumors: ER 24/24 (100%), EGFR 23/24 (95.8%), PR 21/24 (87.5%), p53 19/24 (79.2%), CD10 11/24 (45.8%) with only 4 cases showing positivity in >25% of cells, CD117 4/24 (16.7%) and Her2/neu 0/24 (0%). ER-PR were significantly underexpressed in cases with SO (Fisher exact test: p=0.014 and p=0.001, respectively). A trend toward underexpression of ER-PR in the original tumor of patients who subsequently experienced recurrence was observed, but it did not reach statistical significance. Interestingly, 20 cases showed staining for EGFR in >25% of the cells and 17 cases (including all cases with SO) showed diffuse positivity in >50% of cells.
Conclusions: All cases of AS were at least focally positive for ER and almost all cases for PR. The frequent expression of ER-PR in AS with significant underexpression in cases with SO confirms data from previous studies. The prognostic significance of ER-PR needs to be further assessed. A stromal origin doesn't seem to be a key feature in AS since CD10 was surprisingly expressed in less than half of our cases and consisted of only focal staining (1-25%) in most of them. We did not identify noteworthy expression for CD117 or Her2/neu, but the diffuse positivity for EGFR in most cases of AS is an interesting finding in the era of targeted therapy.
Category: Gynecologic & Obstetrics

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 153, Wednesday Morning


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