The patient's diagnosis was determined to be myeloid/NK cell precursor acute leukemia by morphologic and immunophenotypic analysis (CD7(+)CD33(+)CD34(+)CD56(+)).
This is suggestive of complex multistep tumorigenic mechanisms and is supportive of the hypothesis that CD4(+), CD56(+) DC2 acute leukemia may arise from an undifferentiated nonmyeloid nonlymphoid progenitor cell.
However, 11 adults with AML, and one adult with moab 7.1-positive CD7+ CD56+ myeloid/natural killer cell precursor acute leukemia were negative for MLL rearrangements as proved by Southern blot analysis.
These data suggested that the CD7+ and CD56+ myeloid/NK cell precursor acute leukemia might constitute a distinct biologic and clinical disease entity.