ABSTRACT
<p><b>OBJECTIVE</b>To investigate the myeloperoxidase (cMPO) expression pattern by flow cytometry (FCM) in patients with acute myeloid leukemia (AML) and its role in classifying AML.</p><p><b>METHODS</b>Eight- color multiparametric FCM with CD45/SSC gating was used to determine the cMPO expression in 502 AML patients.</p><p><b>RESULTS</b>The positive rate of cMPO in all patients was 58.0%, in which the proportion of normal positivity, dim positivity and partial positivity was 21.5%, 34.1% and 2.4%, respectively. The remaining case (42.0%) were all negative. In AML with t (15;17）(q22;q12)/PMLRARα, the positive rate was the highest (100%) and the intensity was similar to that of the normal granular leukocytes, followed by AML with t (8;21（q22;q22/RUNX1-RUNX1T1, the positive rate was 91.4% and the intensity was mostly dim. AML with minimal differentiation and acute megakaryoblastic leukemia were all cMPO negative. The positive rates of cMPO in the remaining subtypes were between 22.7% and 76.2%.</p><p><b>CONCLUSION</b>The positive rate and intensity of cMPO were significantly different among different subtypes of AML.</p>