DEN, a chemical carcinogen, can induce hepatoma in mice after injected to 14-day old pups [19], and the tumors found in mice aged over 8 months were all pERK+, determined by Western blot of tumor lysates (Figure 2A) and immunohistochemical staining of tumor sections (Figure 2B). The gene discussed is EIF2AK3; the disease is neoplasm.