MORPHOLOGIC, IMMUNOLOGICAL, AND CYTOGENETIC CLASSIFICATION OF ACUTE MYELOID-LEUKEMIA AND MYELODYSPLASTIC SYNDROME IN CHILDHOOD - A REPORT FROM THE CHILDRENS CANCER GROUP

The purposes of this report are to reaffirm concordance difficulties w ith the acute myeloid leukemia (AML) French-American-British (FAB) cla ssification, to present the frequency of previously delineated AML syn dromes in pediatric patients and to describe additional characteristic AML profiles utilizing composite morphologic, cytogenetic and immunop henotypic data. Profiles of 124 children with acute myeloid leukemia ( AML) and 13 children with myelodysplastic syndrome entered on the Chil drens Cancer Group (CCG) pilot study CCG-2861 were examined. Concordan ce between institutions and reviewers for FAB designation was 65%. Dis cordance was found principally between M1 and M2, M2 and M4, and M4 an d M5. In 49% of marrow specimens, leukemic blasts expressed at least o ne T lineage-related antigen; 24% expressed the B lineage-related anti gen CD19. CDw14 correlated with FAB M4 or M5 morphology and was the on ly surface antigen associated with a specific FAB subtype. Normal kary otypes were found for 15% of the 75 children with satisfactory karyoty pe preparations. Recurring aberrations, found in 76% of children, incl uded t(15;17)(q22;q11), t(8;21)(q22;q22), inv(16)(p13q22), rearrangeme nts of band 11q23, t(6;9)(p23;q34), trisomy 8 and monosomy 7. Results from this pilot study and from the current CCG randomized trial correl ating morphology, immunophenotyping and cytogenetics, will help to cla ssify AML into unique subgroups with differing clinical consequences o r therapy requirements.