We report the pro-proliferation and anti-apoptosis effects of CDCA2 in HCC cells in vitro, discovered its regulation by cyclophilin J (CYPJ), and showed that its function involves activation of the epithelial-mesenchymal transition (EMT) process, the p53/p21 pathway, the p38 MAPK pathway and the JNK/c-Jun pathway. The gene discussed is MAPK8; the disease is hepatocellular carcinoma.