Hepatocellular carcinoma, i.e. malignant tumor of the liver, can be divided into two categories: primary and secondary. Primary liver malignancies originate from the epithelial or mesenchymal tissues of the liver. The former is called primary liver cancer, which is a highly prevalent and dangerous malignancy in China; the latter is called sarcoma, which is less common compared with primary liver cancer. Secondary or metastatic hepatocellular carcinoma refers to the invasion of malignant tumors from multiple organs of the body to the liver. It is usually seen in liver metastases from malignant tumors of stomach, biliary tract, pancreas, colorectum, ovary, uterus, lung, breast and other organs.