Connective Tissue Oncology Society

2001 CTOS Annual Meeting Posters— Biology

GENE EXPRESSION IN LIPOMA, HIBERNOMA, AND LIPOSARCOMA
Keith M Skubitz, Edward C Cheng, Denis R Clohisy, Roby C Thompson, Carlos J Manivel, Amy P Skubitz
University of Minnesota

OBJECTIVE: Malignant transformation is thought to be associated with changes in the expression of a number of genes, and this alteration in gene expression is felt to be critical to the development of the malignant phenotype. In many cases, the progression to malignant transformation is associated with the sequential acquisition of multiple mutations. Sarcomas represent a diverse group of tumors felt to be derived from cells of mesenchymal origin. Marked heterogeneity exists in the biological behavior of sarcomas, even within histologic subtypes of sarcomas. In an effort to better understand the biology of sarcomas, we are examining gene expression using the Affymetrix microarray technology.

METHODS: In this study, the expression of ~60,000 genes/ESTs in lipomas, hibernomas, intra-muscular lipomas, and liposarcomas was determined by Gene Logic. Differences in gene expression were quantified as the fold change in gene expression in lipomas compared with hibernoma, intra-muscular lipoma, atypical lipomatous tumor, and liposarcoma.

RESULTS: Nine genes were expressed greater than 20 fold (1 greater than 70 fold) more in lipomas than in lipomatosis, and 4 were expressed greater than 20 fold more in lipomatosis. Twelve genes were expressed greater than 20 fold (3 greater than 80 fold) more in lipoma than in hibernoma, and 13 were expressed greater than 20 fold more in hibernoma. Interestingly, the thyroid hormone responsive "spot 14" was more highly expressed in lipoma. Eight genes were expressed greater than 50 fold (3 greater than 80 fold) more in lipoma than in intra-muscular lipoma. Seven genes were expressed greater than 20 fold more in lipoma than in liposarcoma, and 1 was expressed greater than 20 fold more in liposarcoma.

CONCLUSION: We conclude that differences in gene expression may help differentiate among subtypes of sarcomas, and may also yield clues to the pathophysiology of this heterogeneous group of tumors.