FGF21 and neoplasm: Phosphorylation of FRS2α, ERK, and AKT, downstream events of FGF21 action (11, 25), was markedly increased in both non-tumorous and tumorous parts of the liver of Atg7ΔHepFgf21+/+ mice and was abrogated in the liver of Atg7ΔHepFgf21−/− mice (Figure 2D).