Molecular Underpinnings and Prevalence of Donor Cell-Derived Hematologic Neoplasms among Spanish Transplantation Centers.

Donor cell-derived hematologic neoplasms occurred in 0.28% of 8,465 allo-HSCTs in Spain (2013–2022), rising after related-donor transplants (0.41% vs 0.06%, p=0.0026).

• Why it matters: The prevalence and molecular basis of donor cell-derived hematologic neoplasms remain poorly defined, limiting risk assessment and donor/recipient evaluation strategies in allo-HSCT.
• What they did: Twenty-four Spanish transplantation centers reviewed allo-HSCT cohorts and required donor-origin confirmation by cytogenetic or molecular testing; molecular work used germline-augmented targeted NGS, whole-exome sequencing, and donor–recipient comparisons.
• The result: Among 39 DDHN cases diagnosed between 2007 and 2025, median latency was 56 months and most were myeloid (51% myelodysplastic neoplasms, 36% acute myeloid leukemia); in 33 characterized cases, germline predisposition predominated with pathogenic/likely pathogenic variants in 10 cases (DDX41 n=7, CEBPA n=2, CHEK2 n=1), all after related-donor transplantation.