Notably, a recent study from Japan on alloHCT for AML performed between 2013 and 2021 with 5704 patients over 50 years of age showed a reduced risk of relapse and increased leukemia-free survival for patients with HLA-A, -B, -C, and -DRB1 compatible unrelated donors when compared to patients with MSD regardless of an age difference [28]. This evidence concerns the gene HLA-A and leukemia.