The percentage of tetramer positive cells was generally lower in the patients and the differences were statistically significant as assayed by Mann-Whitney U test (P<0.05) for 2 out of 3 LMP1 epitopes (YLQ: 0.22 and 0.34, ALL: 0.25 and 0.64, respectively), and 3 out of 4 LMP2 epitopes (LLW: 0.26 and 0.64, GLG: 0.45 and 0.67, FLY: 0.27 and 1.03, respectively). This evidence concerns the gene PSMB9 and acute lymphoblastic leukemia.