Summary
Analysis of the bone marrow karyotype in 109 consecutive untreated patients with acute lymphoblastic leukemia (ALL) by the G-banding technique revealed the presence of a translocation between specific sites on the long arms of chromosomes 4 and 11, [t(4;11) (q21;q23)] in 3 adults and 2 children. Splenomegaly was present in all patients, marked leukocytosis in 4, and retinal hemorrhages in the absence of significant mucocutaneous bleeding in 3. Complete remission defined by conventional morphological criteria was achieved with combination chemotherapy in all instances, but the duration of remission was brief in 3. Three patients were studied in relapse, and clonal evolution was found to have occurred in 2. Analysis of our data in conjunction with other published reports suggests this specific karyotypic abnormality characterizes a small subgroup of ALL in which there is a strong association with recognized clinical and laboratory indices of poor prognosis, in particular its frequent occurrence in children under the age of 2.5 yr. There is a propensity to undergo clonal evolution, and the possibility exists that such a development is associated with poor prognosis.