Isochromosomes in childhood acute lymphoblastic leukemia: a collaborative
study of 83 cases
CH Pui, AJ Carroll, SC Raimondi, MJ Schell, DR Head, JJ Shuster, WM Crist, MJ Borowitz, MP Link and FG Behm
Department of Hematology-Oncology, St Jude Children's Research Hospital,
Memphis, TN 38101.
Cytogenetic analysis of leukemic cells from 2,805 children with newly
diagnosed acute lymphoblastic leukemia (ALL) identified 83 cases (3%) that
had a stemline with at least one isochromosome. The i(9q) was present in 28
(1%), the i(17q) in 23 (0.8%), and the i(7q) in 23 (0.8%). Other
isochromosomes--i(21q), i(6p), i(1q), i(8q), or i(Xq)-- were found in only
12 cases (0.4%). The isochromosome cases were more likely than were other
ALL cases to have a pre-B immunophenotype (38% v 25%, P = .02) and leukemic
cell hyperdiploidy greater than 50 (37% v 24%, P = .02); five cases had
both features. The i(9q) was associated with age greater than 10 years (P
less than .05) and the pre-B immunophenotype (P = .05); both the i(17q) and
i(7q) had high frequencies of hyperdiploidy greater than 50 (P less than
.0001 and P = .05, respectively). The t(1;19)(q23;p13) was a common feature
(23%) in cases with the i(9q), i(7q), i(6p), or i(1q). These findings
establish the i(9q), i(17q), and i(7q) as nonrandom chromosomal
abnormalities in ALL. The prognostic significance of the presence of
isochromosome(s) remains to be determined.
Volume 79,
Issue 9,
pp. 2384-2391,
05/01/1992
Copyright © 1992 by The American Society of Hematology
