Targeting MAPK, PI3K, NF-κB, STAT3 or c-Jun did not decrease PD-L1 levels indicating that other signalling mechanismsmay be involved.A recent report on large numbers of melanoma cell lines revealed that there was no association between BRAF V600E and NRAS mutational status and PD-L1 expression [40].Constitutive expression in lymphomas was reported to be dependent on the ALK and STAT3 axis. This evidence concerns the gene NRAS and melanoma.