IFI6 and melanoma: Therefore, we asked if E2F2 and its target genes involved in the regulation of DNA replication were upregulated in BRAF-mutant, NF1-deficient, or triple wild-type melanoma cells deficient in IFI6. To do so, we knocked down the expression of IFI6 and measured the expression of E2F2 and its target genes (Figure 9—figure supplement 1).