In cancer, cfDNA can be detected a higher concentration in the circulation because of the necrosis of neoplasm cells with the rapid enlargement and relatively shortage of blood supply. So, identifying tumor-specific genetic and epigenetic changes in cfDNA on this status, such as gene mutations, deletions, methylation alterations and microsatellite alterations, may be more specific for us to diagnose the neoplasms in early phase. This phenomenon also appears in the patients with hepatocellular carcinoma (HCC). Studies have shown that cfDNA level is associated with intrahepatic and extrahepatic metastasis in HCC patients and examined some cfDNAcharacteristic changes, such as p161NK4A, RTL, RASSF1A, LINE-1 and GSTP1. Thus is useful for us to explore the specific cfDNA in HCC. For a high sensitivity and specificity detection, we will use technologiesdeveloped at Stanford Genome Technology Centerto find more characteristic gene mutations, methylation alterations or other changes (3). In this study, we willinvestigate thesecharacteristic changesin cfDNA and primary tumor lesions.