Volunteer unrelated donor cell-derived acute myeloid leukemia with RUNX1-RUNX1T1

A 15-year-old male was diagnosed with acute myeloid leukemia with t(6;9)(p23;q34), a chimeric DEK-NUP214 fusion gene. He underwent allogeneic bone marrow transplantation (allo-BMT) from an unrelated volunteer donor at first molecular remission. Approximately 5 years after allo-BMT, multiple bone marrow aspirations showed increased blasts to 63%, which were positive for myeloperoxidase, CD13, CD33, CD56, and CD34. Surprisingly, t(8;21)(q22;q22.1), a chimeric RUNX1-RUNX1T1 (not DEK-NUP214) fusion gene, was detected with full donor chimerism. To our best knowledge, this is the first case of a volunteer unrelated donor cell-derived acute myeloid leukemia harboring a chimeric RUNX1-RUNX1T1 fusion gene.