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Correlation between theETV6/CBFA2 (TEL/AMLI) fusion gene and karyotypic abnormalities in children with B-cell precursor acute lymphoblastic leukemia

1996; Wiley; Volume: 17; Issue: 2 Linguagem: Inglês

10.1002/(sici)1098-2264(199610)17

1098-2264

Scott C. Fears, Christine Vignon, Stefan K. Bohlander, Stephen D. Smith, Janet D. Rowley, Giuseppina Nucifora,

Acute Myeloid Leukemia Research

The recently identified ETV6/CBFA2 (formerly known as TEL/AMLI) fusion gene occurs as a result of the t(12;21)(p12;q22). Initial reports have indicated that the fusion transcript occurs in up to 30% of children diagnosed with B-cell precursor (CD10+,CD19+) acute lymphoblastic leukemia (ALL). In order to characterize the incidence of the t(12;21) at both the chromosomal level as well as the RNA transcript level, we have used a combination of classical cytogenetics, reverse transcriptase-polymerase chain reaction (RT-PCR), and fluorescence in situ hybridization (FISH) to examine the bone marrow of 34 children diagnosed with B-cell precursor ALL Nine of the 34 patient samples expressed the ETV6/CBFA2 transcript. When the results of RT-PCR were compared with the conventional karyotype, the fusion was present in 3 of 10 (33%) with chromosome 12 abnormalities, none of whom had an obvious t(12;21). The transcript was also detected in 5 of the 12 (41%) bone marrow samples with other abnormalities and in 1 of 12 (8%) samples with a normal karyotype. Seven of the 9 RT-PCR positive patient samples were studied with FISH. Of the 7, FISH confirmed the ETV6/CBFA2 fusion in 6. One other patient with a 12p abnormality had evidence for the fusion using FISH which was not detected by RT-PCR. Our results not only confirm that the frequency of the t(12;21) is unusually high in childhood B-cell precursor ALL, but also that none of the translocations in our series was detected with conventional cytogenetic techniques. Genes Chromosom Cancer 17:127–135 (1996). © 1996 Wiley-Liss, Inc.