Journal of Pathology J Pathol 2005; 207: 61–71 Published online 8 July 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/path.1813 Original Paper cDNA expression profiling of chondrosarcomas: Ollier disease resembles solitary tumours and alteration in genes coding for components of energy metabolism occurs with increasing grade Leida B Rozeman, 1 Liesbeth Hameetman, 1 Tom van Wezel, 1 Antonie HM Taminiau, 2 Anne Marie Cleton-Jansen, 1 Pancras CW Hogendoorn 1 and Judith VMG Bov´ ee 1 * 1 Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands 2 Department of Orthopaedic Surgery, Leiden University Medical Center, Leiden, The Netherlands *Correspondence to: Judith VMG Bov´ ee, MD, PhD, Leiden University Medical Center, Department of Pathology, L-1-Q, PO Box 9600, 2300 RC Leiden, The Netherlands. E-mail: J.V.M.G.Bovee@lumc.nl Received: 24 February 2005 Revised: 2 May 2005 Accepted: 7 May 2005 Abstract Conventional central chondrosarcomas are malignant cartilaginous tumours, occasionally arising secondary to either solitary or multiple (Ollier disease) enchondromas. Recurrences may have progressed in grade. The aims of the present study were to identify putative differences in gene expression between solitary and Ollier disease-related tumours, and to elucidate signalling pathways involved in tumour progression by genome-wide cDNA expression analysis. Arrays enriched for cartilage-specific cDNAs and genes involved in general tumourigenesis were used to analyse enchondromas (n = 3, two with Ollier disease), chondrosarcomas of different grades (n = 19, three with Ollier disease), normal resting-zone cartilage (n = 2), and chondrosarcoma cells in culture (n = 7). The arrays were analysed by unsupervised hierarchical clustering, significant analysis of microarray, and T -tests. Confirmation of data was performed by immunohistochemistry and quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Ollier disease cases and solitary tumours revealed similar expression profiles, suggesting that the same signalling pathways are involved in tumourigenesis. Interestingly, JunB protein expression was significantly higher in grade I chondrosarcomas than in enchondromas (p = 0.009), which could be of diagnostic relevance. Upon chondrosarcoma progression, matrix-associated genes are down-regulated, reflecting the histology of high-grade tumours. An increase in glycolysis-associated, and a decrease in oxidative phosphorylation-related, genes was found in high-grade tumours. These findings suggest an adaptation in energy supply upon progression towards higher grade. Copyright  2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Keywords: bone neoplasm; chondrosarcoma; enchondromatosis; oxidative phosphoryla- tion; gene expression profiling Introduction Chondrosarcoma of bone is a malignant hyaline cartilage-forming tumour that affects males and females equally, with a peak incidence around the fifth decade [1]. Most chondrosarcomas (∼83%) arise centrally within the medulla and can develop from a pre-existing enchondroma [1]. A minority (∼17%) are located at the surface of bone (secondary peripheral chondrosarcomas) [1,2]. While most enchondromas are solitary, patients with Ollier disease (enchondromatosis) have multi- ple enchondromas, scattered throughout the skeleton, often with a unilateral predominance [3]. Enchondro- mas of Ollier disease patients display a more indolent clinical behaviour. These enchondromas can contain more worrisome histological features (higher cellular- ity, pleomorphism, and binucleated cells), compared with solitary enchondromas [3,4]. The overall risk of malignant transformation in patients with Ollier dis- ease is higher and has been estimated at 25–30%, compared with less than 1% for solitary enchondromas [3]. Three histological grades of malignancy are distin- guished [5]. Increasing grade correlates with worse prognosis [5,6]. The fact that recurrences of chon- drosarcomas can exhibit a higher grade of malignancy compared with previous lesions suggests that these tumours may progress [5,7]. Little is known about the pathways involved in the development and progression of central chondrosar- comas. Loss of heterozygosity (LOH) analysis shows limited changes, with some recurrent LOH at 9p21 [8]. Increased PTHLH (parathyroid hormone-like hor- mone) signalling is present in high-grade tumours [9,10]. p53 overexpression and mutations [8,11], as well as absence of p16/CDKN2A [12,13], are also found to correlate with high histological grade. Copyright  2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.