High frequency of t(12;21)(p13;q22) in children with acute lymphoblastic leukemia and known clinical outcome in southern Brazil.
The presence of the t(12;21)(p13;q22) distinguishes a subset of children with acute lymphoblastic leukemia (ALL) that present a favorable prognosis. This is a cryptic translocation difficult to detect through conventional cytogenetics. In this study, bone marrow samples from 30 children with ALL from southern Brazil were evaluated by fluorescence in situ hybridization (FISH) for the t(12;21), using locus specific probes to detect the TEL/AML1 rearrangement. The selection criteria included: age (0-12 years old); FAB classification (L1 or L2), absence of specific clonal chromosomal aberrations; and adequate cellular integrity to perform FISH analysis. A frequency of 40% of the t(12;21) was observed, in addition to extra copies of the AML1 gene in 7.5% of patients. These findings were analyzed in relation to the patient's clinical parameters and compared with other pediatric populations.
Departamento de Genética, Laboratório de Citogenética Humana, Universidade Federal do Paraná, Centro Politecnico, Jardim das Americas, Curitiba, PR 81531, Brazil.
Loraine Beatriz Acosta
LB
Veiga
Virginia Maria
VM
Cóser
Luciane Regina
LR
Cavalli
Iglenir João
IJ
Cavalli
Jacqueline Nunes
JN
Rodrigues
Waldir Veiga
WV
Pereira
Dalnei Veiga
DV
Pereira
Thereza Christina Sampaio
TC
Lafayette
Benônio Terra
BT
Villalba
Mauber Eduardo Schultz
ME
Moreira
Bassem R
BR
Haddad
Enilze Maria
EM
de Souza Fonseca Ribeiro
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001853:Bone Marrow / Q000473:pathology; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics*; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D020732:Cytogenetic Analysis; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D007223:Infant; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics*; D011379:Prognosis; D012680:Sensitivity and Specificity; D016896:Treatment Outcome