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Plasticity of melanoma in vivo: murine lesions resulting from Trp53, but not Cdk4 or Arf deregulation, display neural transdifferentiation

Authors


CORRESPONDENCE G. J. Walker, e-mail: Graeme.Walker@qimr.edu.au

Summary

We previously noted that melanomas developing in Cdk4R24C/R24C::Tyr-NRAS, Arf−/−::Tyr-NRAS and Trp53F/F::Tyr-Cre(ER)::Tyr-NRAS mice exhibited differences in behaviour in vivo. We investigated this phenomenon using global gene expression profiling of lesions from the respective genotypes. While those from the Cdk4- and Arf-mutant mice exhibited similar profiles, the Trp53F/F::Tyr-Cre(ER)::Tyr-NRAS melanomas were strikingly different, showing relative down-regulation of melanocyte-related genes, and up-regulation of genes related to neural differentiation. Specifically, they highly expressed genes representative of the myelin-producing peripheral oligodendrite (Schwann cell) lineage, although histopathologically the lesions did not exhibit the classical features of schwannoma. As Schwann cell precursors can be a cellular origin of melanocytes, it is unsurprising that plasticity with respect to melanocyte-neural differentiation can occur in melanoma. What is surprising is the genotype proclivity. Comparison of gene expression signatures revealed that melanomas from the Trp53-mutant mice show significant similarities with a subset of aggressive human melanomas with relatively low levels of MITF.

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