PSMB9 and nasopharyngeal carcinoma: In line within the observation that LMP2 contains several immunodominant HLA-A2 restricted epitopes [19], the PBMCs of healthy donors showed higher frequencies of cells stained with LMP2 compared with LMP1 tetramers (P = 0.003, Mann-Whitney U test), but this difference were not seen in PBMCs from NPC patient.