cDNA expression profiling of chondrosarcomas: Ollier disease resembles solitary tumours and alteration in genes coding for components of energy metabolism occurs with increasing grade

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.