Expression of myeloperoxidase mRNA by leukemic cells from childhood acute lymphoblastic leukemia.

The frequency of acute lymphoblastic leukemia (ALL) expressing the myeloperoxidase (MPO) gene and other myeloid-associated characteristics was determined in 26 (20 B-lineage, six T-lieage) children at diagnosis. All cases were diagnosed as ALL by standard morphological and cytochemical criteria. In the 26 cases, leukemic blast cells from four B-lineage and two T-lineage ALL patients were simultaneously expressing myeloid-associated antigens. By Northern blot analysis, MPO mRNA was detected in leukemic cells from five out of six cases expressing both lymphoid and myeloid antigens, and from four out of 16 B-lineage and one out of four T-lineage ALL without myeloid antigens