Molecular heterogeneity in acute leukemia lineage switch
GA Gagnon, CC Childs, A LeMaistre, M Keating, A Cork, JM Trujillo, K Nellis, E Freireich and SA Stass
Department of Hematology, University of Texas, M.D. Anderson Cancer Center,
Houston.
Six cases of acute leukemia that underwent lineage switch from acute
lymphocytic leukemia to acute myelogenous leukemia are reported. The mean
age of the patients was 24 years, time to conversion was 36 months, and
survival after conversion was only 3 months. Of the three cases which
showed abnormal metaphases at both diagnosis and conversion, two (cases 2,
5) showed related cytogenetic abnormalities, and the third showed (case 3)
independent chromosomal changes. Molecular analysis for immunoglobulin
heavy chain and T-cell receptor beta chain genes showed that five of the
six cases had rearrangement of at least one of these lymphoid associated
genes at conversion to acute myelogenous leukemia. The single case (case 3)
in which there were no lymphoid gene rearrangements at conversion was also
the only case in which independent karyotypic abnormalities at diagnosis
and conversion were demonstrated. Our findings suggest that lineage switch
can represent either relapse of the original clone with heterogeneity at
the molecular level or the emergence of a second new leukemic clone without
molecular heterogeneity.
Volume 74,
Issue 6,
pp. 2088-2095,
11/01/1989
Copyright © 1989 by The American Society of Hematology
