Fig 4.

Reduced induction of interferon-stimulated genes in melanoma compared to normal melanocytes. Quantitative RT-PCR was applied for gene expression studies on control and IFN-αA/D-treated cultures of 11 human melanoma samples and normal human melanocytes. Two specific interferon-stimulated genes (ISGs), Mx1 (A) and OAS (B), were analyzed. β-Actin was used as a reference for each cell type to normalize expression levels. Data reflect the fold induction relative to nontreated control cultures. Normal melanocytes showed induction levels of several thousandfold for both ISGs. In contrast, melanoma tumor cells showed significantly reduced induction of ISGs.