High-risk clonal evolution. Cumulative incidence of high-risk clonal evolution, defined as the acquisition of either chromosome 7 abnormalities, complex cytogenetics, myelodysplastic syndrome, or AML after institution of hATG-based IST, are shown according to the presence or absence of HLA-B*14:02 genotype (A), the presence or absence of HLA loss (B), age groups (C), and 3 risk groups of the prediction model for high-risk clonal evolution incorporating HLA-B*14:02 genotype, HLA loss, and age (D): a high-risk group, any HLA risk (HLA-B*14:02 genotype or HLA loss) present and aged 40 years or older; a low-risk group, no HLA risk present and aged less than 40 years; and an intermediate-risk group, not meeting the criteria for groups of high-risk nor low-risk.