[48] Expression of Markers of Chondrocyte Development in Chondroblastoma and Chondromyxofibroma.

David H Hwang, Anthony G Montag. University of Chicago, IL

Background: Chondrocytes arise from mesenchymal precursors and proceed through distinct stages of development. Chondroblastoma (CB) and chondromyxofibroma (CMF) are benign tumors of bone that have been shown to express some markers that are also expressed during normal chondrocyte development, but the stage of differentiation has not been well characterized.
Design: A tissue microarray was created using 57 chondroblastoma specimens from 34 patients and 11 chondromyxofibroma specimens from 8 patients. The microarray was stained for the following markers grouped by stage of chondrocyte development: Early (fibronectin, N-cadherin, SOX9, collagen I), Mid (SOX9, IGF-1R, aggrecan, PTHrP, STAT1), and Late (beta-catenin, VEGF, collagen I). SOX9 is expressed in both early and mid stages and collagen I is expressed in both early and late stages. These were evaluated using the following scale: 0 (no staining), 1 (<5% staining), 2 (5-50% staining), 3 (>50% staining). Scores of 2 or 3 were considered positive for that marker.
Results: Greater than 50% of specimens of both CBs and CMFs show expression of fibronectin, SOX9, aggrecan, and PTHrP. 86% of CBs show expression of VEGF versus 50% of CMFs, whereas 100% of CMFs express collagen I versus 34.1% of CBs. Both CMFs and CBs show low (less than 50% of specimens) expression of N-cadherin, IGF-1R, STAT1, and beta-catenin.

Percent of Specimens with Positive Expression (Score 2 or 3)
Fibronectin7860 (p=0.24)Sigma
N-cadherin010 (p=0.02)Dako
SOX97856 (p=0.17)R&D System
IGF-1R2530 (p=0.74)Cell Signaling
Aggrecan8090 (p=0.44)Abcam
PTHrP9856 (p<0.01)Novus
STAT11822 (p=0.80)Cell Signaling
Beta-catenin2220 (p=0.91)Zymed
VEGF8650 (p=0.01)Santa Cruz
Collagen I34100 (p<0.01)Abcam

Conclusions: Both chondroblastomas and chondromyxofibromas show marker positivity for all three development stages, but with increased positivity for the mid stage markers. Chondroblastoma shows increased positivity for VEGF, which is a late stage marker.
Category: Bone & Soft Tissue

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 7, Tuesday Morning


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