[Potential role of type I interferon in the genetic progression of melanoma].

We have followed the genomic progression of cutaneous melanoma in visceral metastases using genome-wide copy number analysis. We have detected an increased chromosomal instability due to the loss of several DNA repair genes. Furthermore, we found co-amplifications of HGF and MET genes in metastases. The most interesting finding was gene amplifications of several, mostly IFN-regulated immune cell genes in lung metastases. Next we have defined a type I IFN resistance gene expression signature (GES) using human cell lines, several elements of which were proved to be stable in vitro and in vivo as well. The components of this GES have been detected in TCGA as well as in publicly available datasets of immunotherapy-treated melanoma cases. In case of samples from previously IFN-treated melanoma cases we have identified treatment-specific genomic alterations (predominantly amplifications) which were most characteristic for brain metastases.