Proteomic profiling identifies prognostic subsets in Rhabdomyosarcoma (RMS)

9502 Background: RMS is the most common soft-tissue sarcoma in childhood and is generally sensitive to currently available chemotherapeutic regimens. At present, there is no way to prospectively identify the 30–40% of patients destined to fail initial therapy. We sought to develop a proteomic signature comprised of signal pathway endpoints to predict outcome in a group of uniformly treated children with Stage III RMS and identify new targets for therapy. Methods: Thirty-four pre-treatment patient samples selected on the basis of tissue availability representing both embryonal and alveolar histologies were analyzed employing laser capture microdissection with multiplexed proteomic analysis using reverse phase protein microarray technology. All patients had been entered onto IRS studies and treated with combined chemotherapy and XRT. A panel of 13 specific antibodies was employed based on ongoing work pointing toward specific cell signaling pathways playing a role in the biological behavior of RMS. Validate...