Incidence of TEL/AML1 fusion gene analyzed consecutively in children with acute lymphoblastic leukemia in relapse.
نویسندگان
چکیده
The translocation t(12; 21)(p13; q22) is difficult to detect by classic cytogenetics. However, using fluorescence in situ hybridization (FISH) and by screening for the TEL/AML1 rearrangement by the polymerase chain reaction (PCR), it has been demonstrated to be the most frequent known structural chromosomal abnormality in childhood acute lymphoblastic leukemia (ALL). It is closely correlated with a B-cell precursor (BCP) phenotype and is considered a favorable prognostic factor. However, little is known about the incidence of the translocation in relapsed patients and the duration of complete remission (CR) in children expressing the TEL/AML1 fusion gene. We therefore examined 49 bone marrow samples from children with ALL at first or second relapse that were consecutively mailed to our laboratory to test for the presence of t(12; 21) using reverse transcriptase (RT)-PCR. The TEL/AML1 rearrangement could be identified in nine of 44 (20%) of the patients, a result similar to the reported incidence at diagnosis. Most of the TEL/AML1-positive children showed no adverse clinical features at diagnosis (eg, white blood cell [WBC] count <100 x 10(9)/L or age <10 years), and regarding these data, there were no differences versus children who were negative for the fusion gene. However, the period of remission was about 1 year longer in children expressing TEL/AML1 (P = .046), and the majority of relapses in this group appeared late (<2 years after diagnosis). Our findings therefore reinforce the urgent need for further prospective studies with a long follow-up period to determine the true prognostic significance of t(12; 21) and to avoid premature changes of treatment strategies.
منابع مشابه
Incidence of TEL/AML1 fusion in children with relapsed acute lymphoblastic leukemia.
The TEL/AML1 fusion associated with t(12;21)(p13;q22) is the most common gene rearrangement in childhood leukemia, occurring in approximately 25% of pediatric acute lymphoblastic leukemia (ALL), and is associated with a favorable prognosis. For example, a cohort of pediatric patients with ALL retrospectively analyzed for the TEL/AML1 fusion treated on Dana-Farber Cancer Institute (DFCI) ALL Con...
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Approximately 20% of childhood B-precursor acute lymphoblastic leukemia (ALL) has a TEL-AML1 fusion gene, often in association with deletions of the nonrearranged TEL allele. TEL-AML1 gene fusion appears to be an initiating event and usually occurs before birth, in utero. This subgroup of ALL generally presents with low- or medium-risk features and overall has a very good prognosis. Some patien...
متن کامل[Frequency of TEL/AML1 and BCR/ABL fusion genes in children with acute lymphoblastic leukemia].
BACKGROUND t(12;21) (p12;q22) and t(9;22) (q34;q11) translocations have prognostic significance in acute lymphoblastic leukemia (ALL). The fusion genes TEL/AML1 y BCR/ABL, generated by these translocations, can be easily detected using molecular biology technique. AIM To study the frequency of TEL/AML1 y BCR/ABL fusion genes in children with ALL. MATERIAL AND METHODS Fifty-six children with...
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Acute lymphoblastic leukemia (ALL) accounts for approximately 80% of all acute leukemias during childhood. Chromosomal anomalies resulting from gene fusion, which are frequent in leukemias, create hybrid transcripts, the great majority of which encode transcription factors. We analyzed 88 pediatric patients (median age 7.3 years) who had B-lineage acute lymphoblastic leukemia (B-ALL), using rev...
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عنوان ژورنال:
- Blood
دوره 90 12 شماره
صفحات -
تاریخ انتشار 1997