EIF2AK3 and melanoma: Likewise, TGFβ1 did not alter pERK levels in MEKi-treated melanoma cells (Supplementary Fig. 1A), while there was a slight increase in pERK levels upon TGFβ1 stimulation in some of the cell lines (Supplementary figure 1A), consistent with previous findings that TGFβ can activate the MAPK pathway in a context-dependent manner [35–37].