Increases of serum FGF21 protein levels in mice undergoing hepatocarcinogenesis. Protein levels in sera obtained from mice as indicated were determined by ELISA as described in the Methods section. 20 μl plasma from each mouse was analyzed in duplicate. A : Changes of serum FGF21 levels in mice with deficiency in Hippo pathway components SAV1 and compound MST1/2 (Figure 2B). B : Temporal changes of serum FGF21 levels in mice following DEN-induced hepatocarcinogenesis (Figure 4A). *p < 0.05 (n = 3-4 for each time point).