At the first detection of MLL-ENL, the only topoisomerase II inhibitors the patient had received were one dose of daunorubicin and two doses of etoposide.     ///    "The MLL-ENL fusion was not detectable in blood at the time of ALL diagnosis or after 0.7, 2, 8, 10, and 12 months of therapy but was detectable in blood at 16 months (one in 2.3 x 10(4) cells). "    ///    We used PCR with patient-specific genomic primers to establish the emergence of the MLL-ENL fusion in serially obtained DNA samples.     ///    The MLL-ENL fusion was not detectable in bone marrow at the time of ALL diagnosis or after 2 months of chemotherapy (frequency <8.3 x 10(-7) cells(-1)).     ///    The MLL-ENL and the reciprocal ENL-MLL genomic fusions and their chimeric transcripts were characterized from samples collected at the time of t-AML diagnosis. 