The two neoantigens recognizing T cells identified in this study resulted both from a well-characterized driver gene in myeloid neoplasms (RUNX1; patient DD30) and from a mutation in AP3S1 gene (patient DD31) not known for its role in pathogenesis, which suggests that neoantigens can arise from both driven and passenger mutations in this malignancy. Here, AP3S1 is linked to myeloid neoplasm.