CDKN2A and neoplasm: Primary skin melanoma can be classified into three molecular categories based on gene expression signature: a proliferative one driven by the SOX10–MITF pathway, where CDKN2A is lost; an invasive one characterized by activity of epithelial–mesenchymal transition genes SNAI1, ZEB1 (zinc finger E-box binding homeobox 1) and TGFBR2 (transforming growth factor beta receptor 2); and a so-called immune-mediated one characterized by activation of the tumor microenvironment [8,10].