MAP2K1 and melanoma: To determine potential differences in the sensitivity of pan-negative melanomas to MEK1/2 inhibition, we treated an initial collection of six SNaPshot pan-negative melanoma cell lines (Supplementary Table S3) with the clinically-available MEK1/2 inhibitor, trametinib, and calculated the average IC50 for each in comparison to a well-described BRAF V600E-mutant melanoma line, SK-Mel-28.