Clinicopathologic and cytogenic features of CD34 (My 10)-positive acute nonlymphocytic leukemia.

The authors performed membrane antigen phenotyping on 75 patients with acute nonlymphocytic leukemia with a panel of myeloid-associated monoclonal antibodies. The 34 patients (45%) with CD34-positive leukemia were not significantly different from the 41 with CD34-negative leukemia with respect to age, hemoglobin, white blood cell count, or platelet count at presentation, but their blasts were more likely to lack the CD15 or CD33 antigens and to have FAB M1 or M2 morphologic characteristics. CD34-positive leukemia was more likely to arise after chemotherapy. Patients with CD34-positive leukemia were less likely to enter a complete remission even when analysis was limited to those patients receiving a high-dose induction-type chemotherapy regimen. Giemsa-banding karyotyping studies were obtained in 55 of the cases. In 30 of these cases (56%) clonal karyotypic abnormalities were demonstrated. Although the karyotypic abnormalities and phenotypes were varied, there was a high degree of association between the karyotypic abnormalities monosomy 7/del (7q) and the CD34-positive phenotype; this antigen was expressed on blasts from eight of the nine patients displaying this abnormality. Monoclonal antibody phenotyping of myeloid leukemia with reagents such as anti-CD34 may help to define biologically interesting subsets of ANLL with distinct clinicopathologic expression.