Mouse alveolar rhabdomyosarcoma and wild-type skeletal muscle

The highly aggressive muscle cancer alveolar rhabdomyosarcoma (ARMS) is one of the most common soft tissue sarcoma of childhood, yet the outcome for unresectable and metastatic disease is dismal and unchanged for nearly 3 decades. To better understand the pathogenesis of this disease and to facilitate novel preclinical approaches, we previously developed a conditional mouse model of ARMS by faithfully recapitulating the genetic mutations observed in the human disease, i.e. activation of Pax3:Fkhr fusion gene with either p53 or Cdkn2a inactivation. In this report we show that this model recapitulates the immunohistochemical profile and the rapid progression of the human disease. We demonstrate that Pax3:Fkhr expression increases during late preneoplasia, but that tumor cells undergoing metastasis are under apparent selection for Pax3:Fkhr expression. At a whole genome level, a cross-species gene set enrichment analysis and metagene projection study showed that our mouse model is most similar to human ARMS when compared to other pediatric cancers. We have defined an expression profile conserved between mouse and human ARMS as well as a Pax3:Fkhr signature, including the target gene, SKP2. We further identified 7 druggable kinases over-expressed across species. The data affirms the accuracy of this genetically engineered mouse model.

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Nishijo K, Chen QR, Zhang L, McCleish AT, Rodriguez A, Cho MJ, Prajapati SI, Gelfond JA, Chisholm GB, Michalek JE, Aronow BJ, Barr FG, Randall RL, Ladanyi M, Qualman SJ, Rubin BP, LeGallo RD, Wang C, Khan J, Keller C