Are all sarcomas to be treated the same?

[D.ap]

Researchers Find Remarkable Heterogeneity in Sarcomas


By Alice Goodman
December 15, 2011, Volume 2, Issue 18

Over 100 Subtypes

2.18.59_blay.jpg“Sarcoma is a heterogeneous group of more than 50 histotypes, without taking grading into account, and there are probably more than 100 molecular subtypes, Dr. Blay told listeners at the recent European Multidisciplinary Cancer Congress in Stockholm.

Although these discoveries are exciting, adapting treatment of sarcomas according to histology is still controversial for most subtypes at present, Dr. Blay noted. He and his colleagues are presently working on two large sets of research projects in this area. One is testing new treatments that target a protein or pathway that is driving a particular tumor subtype. In addition, the group is studying sarcomas without known driving forces—those with complex genetic alterations—and looking for additional mutations that may be responsible for tumor growth.

Sarcoma Subgroups

Five subgroups of sarcomas have been identified:
•Sarcomas with specific translocations and fusion oncogenes (Ewing’s sarcoma, synovial sarcoma, alveolar rhabdomyosarcoma, and desmoplastic small round cell tumor)
•Sarcomas with tyrosine kinase mutations (KIT in gastrointestinal stromal tumor [GIST])
•Sarcomas with deletion of tumor suppressor genes (rhabdoid tumors)
•Sarcomas with a single genetic alteration (well-differentiated or dedifferentiated liposarcomas)
•Sarcomas with complex genetic alterations (leiomyosarcomas, malignant fibrous histiocytoma, undifferentiated and pleiomorphic sarcomas, osteosarcomas); these tumors have chromosome instability and are associated with a worse prognosis

“The ability to subclassify sarcomas gives us the opportunity to determine which subsets predict for response to adjuvant and neoadjuvant therapy for a very complex group of diseases,” Dr. Blay continued.



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