Aggressive neoplastic plasma cell growth with MLL gene rearrangement afterhigh-dose therapy with autologous stem cell support for multiple myeloma

We report a case of a patient with IgA kappa multiple myeloma (MR I) mobili zed with etoposide and subsequently receiving high-dose melphalan (HDM) wit h stem cell support. She relapsed rapidly post transplantation. Southern bl ot and fluorescent in situ hybridization analysis showed MLL gene rearrange ment in the myeloma cells, which was not detected in the sample at diagnosi s or in the PBSC harvested with etoposide plus G-CSF, These observations su ggest that clonal rearrangement of the MLL gene is caused by etoposide, Pat ients with MM undergoing HDM with stem cell rescue may be at an increased r isk of not only secondary leukemia, but also secondary genetic abnormalitie s in myeloma cells, especially those receiving priming with etoposide for p eripheral blood stem cell collection.