IRF1 and melanoma: Furthermore, the results suggest that a subgroup of dedifferentiated melanoma cells expresses increased levels of PD-L1, CCL2 and IL-8 in response to IFNγ, with IRF1 expression contributing highly to the upregulated inflammatory signaling responses of PD-L1high expressing cells (Fig. 10, Supplementary Fig. S10, Supplementary Fig. S14).