Interphase cytogenetic analysis of clonality in peripheral blood cells from a patient with Down syndrome and acute megakaryoblastic leukemia.
A combination of fluorescence-activated cell sorting and interphase fluorescence in situ hybridization (FISH) techniques was used to detect a clonal chromosomal marker in blasts, granulocytes, and T and B lymphocytes of the peripheral blood from a patient with Down syndrome and acute megakaryoblastic leukemia (AMKL) associated with trisomy 8 as a karyotypic abnormality. Immunophenotypic studies with flow cytometry showed two populations of leukemic blasts distinguished by their expression of the CD34 antigen. Interphase FISH studies revealed clonal trisomy 8 FISH signals in almost all blast cells, regardless of CD34 expression, as well as in a small subpopulation of granulocytes. Normal chromosome 8 signal patterns were detected in T and B cells and in a great majority of granulocytes. The present study provides evidence for the clonal involvement of leukemic blasts in AMKL of Down syndrome, indicating that a trisomy 8 abnormality may be a primary event in leukemogenesis. The transformation occurs in progenitor cells with limited myeloid differentiation and without involvement of lymphoid lineage cells.
Chang
Hong
H
Princess Margaret Hospital, University Health Network, University of Toronto, 4-320 Toronto, Ontario M5G 2M9, Canada. hong.chang@uhn.on.ca
Li
Dan
D
Nayar
Rakash
R
Ye
Charles
C
Lau
Wendy
W
Sutherland
D Robert
DR
D018952:Antigens, CD34 / Q000235:genetics; D002675:Child, Preschool; D020732:Cytogenetic Analysis; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase; D007947:Leukemia, Megakaryoblastic, Acute / Q000235:genetics*
D018952:Antigens, CD34