Demonstration of acquired hemizygosity and clonality in acute lymphoblastic leukemia with chromosome 7 abnormalities using hypervariable DNA probes.
Clonal abnormalities of chromosome(s) 7 were investigated in two patients with acute lymphoblastic leukemia. The abnormal karyotypes were 46,XY,-7,del(6)(q13q21), + i(7q)/47,XY,del(6), + i(7q) in case 1, and 46,XX,-7,t(4;11)(q21;q23), + i(7q) in case 2. DNA from leukemic tissue was investigated with Southern blotting using hypervariable DNA probes lambda MS31 and p lambda g3 located on 7p and 7q, respectively. Restriction fragment length polymorphisms (RFLPs) were detected on the short arm in case 1 and on both arms in case 2, and a marked difference in intensity between the two alleles was observed. In case 1 the acquired hemizygosity of 7p, suggested by the cytogenetic findings, was confirmed by Southern blotting. Thus, one chromosome 7 formed the i(7q) and the other No. 7 was duplicated. In case 2 the results of the Southern blotting indicated that the size of the clone with i(7q) was considerably greater than suggested by cytogenetic analysis of the few available metaphase cells.
Yamada
T
T
Department of Haematology, Royal Free Hospital, London, United Kingdom.
Shippey
C A
CA
Martineau
M
M
Secker-Walker
L M
LM
D000293:Adolescent; D015139:Blotting, Southern; D002869:Chromosome Aberrations; D002872:Chromosome Deletion; D002897:Chromosomes, Human, Pair 7 / Q000648:ultrastructure*; D002999:Clone Cells / Q000648:ultrastructure; D015342:DNA Probes; D005260:Female; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D005810:Multigene Family; D014411:Neoplastic Stem Cells / Q000648:ultrastructure; D012150:Polymorphism, Restriction Fragment Length; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*
D015342:DNA Probes