High frequency of t(12;21)(p13;q22) in children with acute lymphoblastic leukemia and known clinical outcome in southern Brazil

• Published in: Leukemia research Vol. 28; no. 10; pp. 1033 - 1038
• Main Authors: Veiga, Loraine Beatriz Acosta, Cóser, Virginia Maria, Cavalli, Luciane Regina, Cavalli, Iglenir João, Rodrigues, Jacqueline Nunes, Pereira, Waldir Veiga, Pereira, Dalnei Veiga, Lafayette, Thereza Christina Sampaio, Villalba, Benônio Terra, Moreira, Mauber Eduardo Schultz, Haddad, Bassem R, Ribeiro, Enilze Maria de Souza Fonseca
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2004
• Subjects: AML1/ TEL fusion; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Bone Marrow - pathology; Brazil; Child; Child, Preschool; Chromosomes, Human, Pair 12 - genetics; Chromosomes, Human, Pair 21 - genetics; Clinical outcome; Cytogenetic Analysis; Cytogenetics; Female; FISH; Humans; In Situ Hybridization, Fluorescence - methods; Infant; Male; Pediatric ALL; Precursor Cell Lymphoblastic Leukemia-Lymphoma - diagnosis; Precursor Cell Lymphoblastic Leukemia-Lymphoma - drug therapy; Precursor Cell Lymphoblastic Leukemia-Lymphoma - genetics; Prognosis; Sensitivity and Specificity; t(12:21); Treatment Outcome; Brazil; FISH; Cytogenetics; Clinical outcome; Pediatric ALL; AML1/ TEL fusion; t(12:21)
• ISSN: 0145-2126; 1873-5835
• DOI: 10.1016/j.leukres.2004.02.004

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.