[48] SOX11 Is a Marker for Myxoid/Round Cell Liposarcoma

Krister J Jones, Nicole D Riddle, John S Brooks, Jui-Han Huang. Pennsylvania Hospital, Philadelphia, PA

Background: Histologic classification of myxoid lesions by histology alone can pose a diagnostic challenge, especially with limited biopsy material. We hypothesized that publicly available gene expression microarray databases may yield candidate genes of potential value in discriminating between myxoid neoplasms. This bioinformatics-based approach indeed suggested that the transcription factor SOX11 (Sry-related HMG-box-11) is highly expressed by myxoid liposarcomas. With the goal of more accurate diagnosis of these lesions, we therefore evaluated the reactivity of SOX11 in a range of myxoid neoplasms: myxoid/round cell liposarcoma (MRC-LPS), intramuscular myxoma (IMM), myxofibrosarcoma (MYFS), and dedifferentiated liposarcoma (DD-LPS).
Design: A total of 18 MRC-LPS, 20 IMM, 28 MYFS, and 32 DD-LPS were retrieved and reviewed. Tissue microarrays (TMAs) were constructed in duplicate. TMAs, as well as whole sections, were evaluated for immunoreactivity to SOX11 (Sigma, rabbit, HPA000536, 1:100). Independent scoring by two of the investigators (KJJ and JHH) for the percentage of tumor cells demonstrating nuclear reactivity and intensity of expression (score 0, 1, 2, 3) yielded an immunohistochemistry score (0-300). A threshold for positive reactivity was set at an IHC score of 100.
Results: Nearly all MRC-LPS cases (16/18, 89%) demonstrated positive immunoreactivity for SOX11. SOX11 immunoreactivity was absent to rare in cases of IMM (0/20, 0%), MYFS (1/28, 3.6%), and DD-LPS (3/32, 9.4%).

The positive SOX11 marked the monster cells in one MYFS case and the areas of high grade DD-LPS cases. SOX11 immunoreactivity was negative or decreased within the maturing adipocytic component of MRC-LPS tumors. Normal fat was negative.
Conclusions: 1) Publicly available gene expression microarray databases may be a source for markers of potential diagnostic use; 2) SOX11 transcription factor is frequently expressed in myxoid liposarcomas; 3) SOX11 is absent to rare in myxomas, myxofibrosarcomas, and dedifferentiated liposarcomas; 4) Thus, this differential immunoreactivity strongly suggests SOX11 immunohistochemistry has potential diagnostic utility for the diagnostic evaluation of myxoid lesions, including small needle biopsy material.
Category: Bone & Soft Tissue

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 12, Monday Morning


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