Project description:We measured the expression profiles of a series of 30 Rhabdomyosarcoma biopsy samples (15 embryonal RMS, 10 translocation-positive alveolar RMS and 5 translocation-negative alveolar RMS). Expression data was used for unsupervised hierarchical clustering as well as supervised analysis to find gene expression signatures characteristic for the different histological RMS subgroups.
Project description:Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Prognosis for patients with high grade and metastatic disease is still very poor, and survivors are burdened with long-lasting side effects. Therefore, more effective and less toxic therapies are needed. Surface proteins are ideal targets for antibody-based therapies, like bispecific antibodies, antibody drug conjugates, or chimeric antigen receptor (CAR) T cell. Specific surface targets for RMS are scarce. Here, we performed a surfaceome profiling based on differential centrifugation enrichment of surface/membrane proteins and detection by LC-MS on six fusion-positive (FP) RMS cell lines, five fusion-negative (FN) RMS cell lines, and three RMS patient-derived xenografts (PDXs). 699 proteins were detected in the three RMS groups. Ranking based on expression levels and comparison to expression in normal MRC-5 fibroblasts and myoblasts, followed by statistical analysis, highlighted known RMS targets such as FGFR4, NCAM1, and CD276/B7-H3, and revealed AGRL2, JAM3, MEGF10, GPC4, CADM2, as potential targets for immunotherapies of RMS. L1CAM expression was investigated in RMS tissues and strong L1CAM expression was observed in more than 80% of alveolar RMS tumors, making it a practicable target for antibody-based therapies of alveolar RMS.
Project description:To elucidate the pathogenesis of rhabdomyosarcoma (RMS), particularly for different subgroups, we performed a SNP array-based copy number analysis of 54 RMS specimens from primary cases with ERMS (N = 30), ARMS (N = 14), unclassified RMS (N = 1), and RMS of unknown histology (N = 3) together with 7 RMS-derived cell lines. The ERMS subtype was characterized by hyperploidy and was significantly associated with gains of chromosomes 2, 8, and 12, whereas majority of ARMS cases exhibited near-diploid copy number profiles. Recurrent loss of heterozygosity (LOH) of chromosomes 3 (28.6%) and 15q (35.7%) was detected in ARMS. Uniparental disomy/polysomy of 11p was commonly found in both tumor types. Focal gains/amplifications were associated mostly with PAX3-FOXO1 (5/10) or PAX7-FOXO1 (6/6) fusions, but novel amplified regions were also found, including the IRS2 in 2 ARMS. Gain of 13q was significantly associated with good patient outcome in ERMS. These findings not only illustrate genetic differences between ARMS and ERMS but also provide novel insights into the pathogenesis of RMS.
Project description:To elucidate the pathogenesis of rhabdomyosarcoma (RMS), particularly for different subgroups, we performed a SNP array-based copy number analysis of 46 RMS specimens from primary cases with ERMS (N = 21), ARMS (N = 14), unclassified RMS (N = 1), and RMS of unknown histology (N = 3) together with 7 RMS-derived cell lines. The ERMS subtype was characterized by hyperploidy and was significantly associated with gains of chromosomes 2, 8, and 12, whereas majority of ARMS cases exhibited near-diploid copy number profiles. Recurrent loss of heterozygosity (LOH) of chromosomes 3 (28.6%) and 15q (35.7%) was detected in ARMS. Uniparental disomy/polysomy of 11p was commonly found in both tumor types. Focal gains/amplifications were associated mostly with PAX3-FOXO1 (5/10) or PAX7-FOXO1 (6/6) fusions, but novel amplified regions were also found, including the IRS2 in 2 ARMS. Gain of 13q was significantly associated with good patient outcome in ERMS. These findings not only illustrate genetic differences between ARMS and ERMS but also provide novel insights into the pathogenesis of RMS. Copy number analysis of Affymetrix 50K/250K SNP arrays was performed for 46 RMS samples.