Characterization of childhood acute leukemia with multiple myeloid and lymphoid markers at diagnosis and at relapse.
To define the clinical and biologic significance of childhood acute mixed-lineage leukemia diagnosed by stringent criteria, we studied 25 cases of acute lymphoblastic leukemia expressing greater than or equal to 2 myeloid-associated antigens (My+ ALL), and 16 cases of acute myeloid leukemia expressing greater than or equal to 2 lymphoid associated antigens (Ly+ AML). These cases represented 6.1% of 410 newly diagnosed ALLs (two treatment protocols) and 16.8% of 95 AMLs (two protocols). T-lineage--associated antigens were identified in 9 of the My+ ALL cases and in 14 of those classified as Ly+ AML; all but 1 of the 19 cases that could be subclassified had an early thymocyte stage of differentiation. The My+ ALL cases had an increased frequency of French-American-British (FAB) L2 morphology (36%); the Ly+ AML cases were characterized by FAB M1 or M2 morphology, low levels of myeloperoxidase reactivity and combined populations of myeloperoxidase-positive large blasts and small blasts generally of hand-mirror morphology. Karyotypic abnormalities included t(9;22)(q34;q11) in three cases of My+ ALL, 11q23 translocations in two cases of My+ ALL, and 14q32 translocations in three My+ ALL and five Ly+ AML cases. Mixed-lineage expression lacked prognostic significance in either ALL or AML; however, the findings indicate that some patients with Ly+ AML may respond to prednisone, vincristine, and L-asparaginase after failing on protocols for myeloid leukemia. At relapse, two My+ ALLs had converted to AML and two Ly+ AMLs to ALL; one case in each group showed complete replacement of the original karyotype. Acute mixed-lineage leukemia does not adequately describe the heterogeneity of the cases identified in this study and should be replaced by a set of more restrictive terms that indicate the unique biologic features of these leukemias.
Pui
C H
CH
Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, TN 38101.
Raimondi
S C
SC
Head
D R
DR
Schell
M J
MJ
Rivera
G K
GK
Mirro
J
J
Crist
W M
WM
Behm
F G
FG
D000293:Adolescent; D015703:Antigens, CD / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations / Q000175:diagnosis; D025063:Chromosome Disorders; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D007621:Karyotyping; D015456:Leukemia, Biphenotypic, Acute / Q000188:drug therapy / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D012008:Recurrence; D012074:Remission Induction; D016019:Survival Analysis
D015703:Antigens, CD