The non-random dic(9;12) translocation in acute lymphoblastic leukemia is associated with B-progenitor phenotype and an excellent prognosis.
A dicentric translocation involving the short arms (p) of chromosomes 9 and 12 was identified in 15 of 2303 successfully banded cases of acute lymphoblastic leukemia (ALL) in children, consecutively entered on protocols of the Pediatric Oncology Group (1986-1990) or St Jude Children's Research Hospital (1984 and 1990). The dic(9;12)(p1?1;p1?2) was seen only in patients with a B progenitor cell immunophenotype: the frequency was 0.8% among pre-B cases (4/508) and 0.9% (11/1177) among early pre-B cases. Laboratory and clinical characteristics were similar to those of the general population of children with ALL, with the exception of a marked male preponderance (12/15 cases). Flow cytometric studies revealed a leukemic cell DNA index of 1.0 in all cases. All fifteen patients are in continuous complete remission at a median follow-up duration of 57+ months (range 9-93+ months). These findings suggest that the dic(9;12) is a recurrent chromosomal translocation in pediatric ALL, occurs exclusively in B-progenitor ALL, and unlike other non-random translocations, is associated with an excellent prognosis.
Mahmoud
H
H
Department of Hematology-Oncology, St Jude Children's Research Hospital, Memphis, TN 38101.
Carroll
A J
AJ
Behm
F
F
Raimondi
S C
SC
Schuster
J
J
Borowitz
M
M
Land
V
V
Pullen
D J
DJ
Vietti
T J
TJ
Crist
W
W
D000293:Adolescent; D001402:B-Lymphocytes; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations / Q000235:genetics*; D025063:Chromosome Disorders; D002881:Chromosomes, Human, Pair 12; D002899:Chromosomes, Human, Pair 9; D006801:Humans; D007223:Infant; D007621:Karyotyping; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D011379:Prognosis; D014178:Translocation, Genetic