Human Leukocyte Antigen (HLA) is another type of protein. An HLA pre-screening test will be able to show if a person is positive or negative for a specific HLA protein (AST-VAC2 can only work with some types of HLA), as being positive for the protein may mean there is a better chance of the vaccine attacking the cancer. Patients who are positive for the specific HLA type will be asked to consent to the vaccine arm i.e. to receive the study vaccine. Those patients who are negative for the HLA type will be asked to consent to a control arm and will not receive the study vaccine.