High frequency of t(12;21) in childhood acute lymphoblastic leukemia detected by RT-PCR.
Recently, a new recurrent translocation, t(12;21)(p13;q22), has been identified in B-cell lineage acute lymphoblastic leukemia (ALL). The translocation results in the fusion of two known genes, ETV6/TEL(12p13) and AML1(21q22), both of which have been shown to be involved in other hematological malignancies. The t(12;21) is virtually undetectable by routine cytogenetics, but the chimeric transcript ETV6-AML1 has been detected in childhood ALL by molecular techniques in up to 36% of cases, making it the most common genetic abnormality in these patients. It has been shown to be associated with a B-precursor phenotype and an excellent prognosis. We tested 66 diagnostic pediatric ALL samples by reverse transcription polymerase chain reaction (RT-PCR) and found evidence of the t(12;21) in 22 (33%). None of these had previously been identified as harboring the t(12;21), although six had karyotypic abnormalities involving either 12p13 or 21q22. ETV6-AML1 expression defined a subgroup of patients characterised by an age of between two and 12 years, B-lineage immunophenotype and non-hyperdiploid DNA content. Our data further support the importance of molecular diagnostic methods in the identification of clinically distinct subgroups of patients with ALL.
Amor
D J
DJ
Department of Hematology and Oncology, Royal Children's Hospital, Melbourne, Victoria, Australia.
Algar
E M
EM
Slater
H R
HR
Smith
P J
PJ
D002648:Child; D002675:Child, Preschool; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics*; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D004273:DNA, Neoplasm / Q000032:analysis*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014178:Translocation, Genetic / Q000235:genetics*; D016896:Treatment Outcome
D017931:DNA Primers; D004273:DNA, Neoplasm