MAP2K1 and cancer: Given that inhibition of MEK1/2 pathway elevates IRF1-dependent interferon response in RAS-transformed fibroblasts (25) and cancer cells (26, 27), whether and how activated MEK1/2 pathway inhibits IRF1 to constrain the interferon response in cell types like keratinocyte (28) and TLR-activated macrophage (29) awaits further scrutiny.