ORLANDOGenetic "fingerprinting" of high-grade adult soft-tissue sarcomas by oligonucleotide array ("gene chip") analysis revealed a number of distinct tumor subsets and might help point to new therapeutic approaches, Robert G. Maki, MD, PhD, said at the 38th Annual Meeting of the American Society of Clinical Oncology (abstract 1611).
"For example, samples that show high expression of certain human growth factor receptors may be targets for imatinib(Drug information on imatinib) mesylate [Gleevec]," he commented.
Dr. Maki, Dr. Neil Segal, and their colleagues from Memorial Sloan-Kettering Cancer Center used gene chips to examine the activity patterns of 12,500 genes in 51 samples of various adult soft-tissue sarcomas. Sarcomas, which constitute less than 1% of all cancers, are very hetereogenous, he said. Tissue diagnosis is critical. "You want to make sure you’re not dealing with epithelial cancer or something else," Dr. Maki said, adding that treatment does vary among different types of sarcoma.
"Genetic fingerprinting of adult sarcomas will be useful in cases where pathologists disagree about a diagnosis or when the appearance of tumor cells does not conclusively link them to a particular subtype," Dr. Maki said.
His presentation focused extensively on malignant fibrous histiocytoma (MFH), which has been something of a catchall diagnostic category for ambiguous sarcomas. The genetic fingerprinting showed that certain MFH sarcomas are, indeed, a distinct tumor subtype.
The researchers prepared complementary RNAs (cRNAs) from 51 high-grade adult soft-tissue sarcomas. These were hybridized to U95A Affymetrix gene chips, and difference values were generated corresponding to levels of expression of approximately 12,500 genes.
Cluster analysis was done using hierarchical clustering, and data were visualized by multidimensional scaling.