[Genomic alterations of invasive melanoma cells]

Tumour cell invasion is the first step in metastasis, during which cells are able to infiltrate surrounding tissues. We aimed to investigate genetic and epigenetic differences associated with the invasiveness in melanoma. To determine the invasiveness of cells, we used Matrigel invasion chamber. Genetic analyses were performed by array CGH, DNA methylation was assessed by Illumina array, gene expression changes were determined by Affymetrix array. Our results showed significantly higher copy numbers of GDNF, GPAA1, PLEC and SHARPIN genes in invasive cells compared to non-invasive ones. We observed that the invasive cells were characterized by a hypermethylated pattern. Most of the hypermethylated genes were associated with decreased expression, however, increased gene expression was observed for EGFR and RBP4 genes with hypermethylation extending into the gene body. Hypermethylation of the ARHGAP22 and NAV2 genes characterized invasive cells and melanoma metastasis samples. Our results point to the hypermethylation pattern of invasive cells, which may be related to the invasive property.