In parallel with these alterations in oxidative stress markers, we detected significantly reduced immunostaining for KDEL (a signal motif for ER retrieval) and C/EBP homologous protein (CHOP; a marker for ER stress–induced cell death) in the livers from Stk25 knockout mice with both DEN- and CDAA-induced HCC (Figure 6A and B). This evidence concerns the gene DDIT3 and hepatocellular carcinoma.