[Secondary leukemia after etoposide treatment involved MLL gene rearrangement]

The 11q23 chromosomal abnormality is frequently observed in infantile leukemia and secondary leukemia, and the translocation associated gene in infantile leukemia is called mixed-lineage leukemia (MLL) gene. A 50-year-old man was admitted because of left axillary lymphadenopathy and IBL like T cell lymphoma was diagnosed by lymph node biopsy. The patient responded to the LSG-9 protocol with complete remission. After 10 months he was readmitted because of fever and was diagnosed acute myeloblastic leukemia by bone marrow aspiration. Chromosome analysis revealed 11q23 abnormality, suggesting that the leukemia was induced by etoposide treatment. Southern blot analysis demonstrated DNA rearrangement in the MLL gene at 11q23. It was suggested that the breakpoint region of the MLL gene in secondary leukemia is the same as that of infantile leukemia.