On the basis of negativity for myeloperoxidase (MPO) and absence of lineage-associated antigens on the cell surface, 11 children were diagnosed as having acute undifferentiated leukemia.
Of these cases, 7 were diagnosed as acute undifferentiated leukemia (AUL) whose leukemic cells were negative formyeloperoxidase and did not react with lineage-specific or lineage-associated monoclonal antibodies.