Evaluation of Immune Responses and Outcomes in Patients With Hepatocellular Carcinoma Undergoing Radiotherapy

Inclusion Criteria: 1. Participants must have diagnosis of HCC. Participants may have multiple lesions. Diagnosis should be confirmed by at least 1 criteria listed below: * Histologically or cytologically proven diagnosis of HCC. * Typical arterial enhancement and delayed washout on multiphasic CT or MRI. 2. Age ≥18 years at the time of signing informed consent document. 3. ECOG performance status 0-2. 4. Child-Pugh score 5-9 liver function within 28 days of study registration. 5. Documented virology status of hepatitis B virus (HBV), as confirmed by screening HBV serology test. 6. Documented virology status of hepatitis C virus (HCV), as confirmed by screening HCV serology test. 7. Ability to understand and the willingness to sign a written informed consent document Exclusion Criteria: 1. Presence of distant metastases that cannot be encompassed by radiotherapy 2. Pregnancy or women of childbearing potential and men who are sexually active and not willing/able to use medically acceptable forms of contraception 3. Inability to treat all sites of disease by radiotherapy 4. Known HIV infection.