Notably, in a diethylnitrosamine (DEN)-induced liver carcinogenesis animal model, PAK1 overexpression was observed along HCC progression, together with the upregulation of cyclin D1 and activation of ERK1/2, p38 as well as JNK1/2 kinases [68], strongly suggesting its contribution in HCC development and progression. The gene discussed is CCND1; the disease is hepatocellular carcinoma.