Metformin Plus Sorafenib for Advanced HCC

Inclusion Criteria: 1. Ability of the research subject or authorized legal representative to understand and the willingness to sign a written informed consent document 2. Confirmed hepatocellular carcinoma according to one of following three criteria: histopathology,Two radiographic techniques (US, MRI, CT, or Angiography) that confirm lesion with typical arterial hypervascularization,Barcelona Clinical Liver Cancer staging C (BCLC-C) 3. Age \> 18 years old 4. Patients with liver disease classified as Child Pugh class A 5. Eastern Clinical Oncology Group (ECOG) performance status 0，1 or 2 (Appendix I) 6. Hemoglobin ≥ 9 g/dL 7. Absolute Neutrophil count（ANC）≥ 1,500 /mm3 8. Platelet count≥ 50,000 /ul 9. Total Bilirubin \< 2 mg/dL 10. Transaminases (SGOT and SGPT) no more than 5 times the upper limit of normal 11. Alkaline phosphatase \< 4 times the upper limit of normal 12. Both men and women and members of all races and ethnic groups are eligible for this study 13. Prothrombin time \> 50% 或 PT-INR \< 2.3 Exclusion Criteria: 1. Child Pugh Score is 7 with ascites 2. Severe cardiovascular disease 3. Uncontrollable hypertension 4. History of HIV infection 5. Active clinical severe infection（\>grade 2 ，NCI-CTCAE Version3.0） 6. Women who are pregnant 7. Administration of any systemic chemotherapy within the last 6 months 8. Presence of History of gastrointestinal bleeding before randomization 9. Epileptic seizures requiring drug therapy 10. History of allograft transplantation 11. Patients with signs of bleeding or medical history 12. Patients undergoing kidney dialysis 13. Metastatic liver cancer 14. Uncontrollable ascites 15. Encephalopathy