HLA-A and neoplasm: To validate the binding competition assay, a set of 12 HLA-A*02:01 peptide ligands derived from viral proteins and 8 known peptide ligands from tumor-associated antigens as well as 7 non-A*02:01 binders was then tested with pp65 N9VFITC competitor peptide (Figure 6B, see Supplementary Table 3 for predicted %Rank EL values).