Expression of Mesenchymal Developmental Antigens in Chordoma
Selene Koo, Anthony G Montag. University of Chicago, Chicago, IL
Background: Chordomas are thought to derive from notochordal remnants. The transcription factor brachyury is a specific marker for chordomas that is expressed in all stages of notochord formation, but expression of other developmental antigens has not been broadly studied in chordomas. This study explores the expression in chordomas of proteins important for embryonal notochord and somite development and compares it with expression in other myxoid tumors.
Design: With IRB approval, cases were retrieved from the paraffin archive, and a tissue microarray was prepared with duplicate cores from 20 chordoma cases from 12 patients, 7 cases of intramuscular myxoma, and 3 cases of extraskeletal myxoid chondrosarcoma (EMC). Immunohistochemical stains were performed for beta-catenin, Bmp2, fibronectin, Foxa2, Noggin, Notch-1, Noto, Pax8, quaking, and Sox9, and reactivity scored as positive (>10%) or weak to negative (≤10%). When discrepancies in reactivity occurred between paired cores, the higher value was used.
Results: Staining results are summarized in the table below.