To elucidate the contribution of MX2 and XAF1 to the growth‐inhibitory effect of IFNα, we investigated the proliferation of two BRAF and two NRAS mutant melanoma cultures after either MX2 or XAF1 downregulation followed by 48‐h IFNα incubation (protein expression assessed in Figure S3D,E). The gene discussed is MX2; the disease is melanoma.