Prognostic significance of TEL/AML1 fusion transcript in childhood B-precursor acute lymphoblastic leukemia.
OBJECTIVE
A retrospective study was conducted to investigate the prognostic significance of TEL/AML1 fusion resulting from a cryptic t(12;21) in Japanese patients with childhood B-precursor acute lymphoblastic leukemia (ALL).


METHODS
Leukemic samples from 144 children with newly diagnosed ALL (104 with CD10-positive B-precursor ALL, 11 with CD10-negative B-precursor ALL, 5 with B-ALL, and 24 with T-ALL) were analyzed by reverse-transcription polymerase chain reaction.


RESULTS
The frequency of patients with TEL/AML1 was 16% (23 of 144) and all patients with TEL/AML1 also had CD10-positive B-precursor ALL. TEL/AML1 was not found in any samples from the patients with T-ALL, B-ALL, or CD10-negative B-precursor ALL. Among patients with CD10-positive B-precursor ALL, age, initial white blood cell count, and immunophenotype did not differ with TEL/AML1 positivity, although the patients were predominantly male (p < 0.01). Clinical outcomes of 94 patients treated with recent protocols were analyzed. Five of the 21 (23.8%) patients with TEL/AML1 relapsed and 4 of these relapsed > 24 months after diagnosis. Although the overall 5-year survival rate was better among patients with TEL/AML1 fusion transcript than among those without it (87.3 +/- 8.7% versus 75.9 +/- 5.8%, respectively), the 5-year disease-free survival (DFS) rates of patients with TEL/AML1 fusion transcript and those without it were similar (64.0 +/- 13.5% versus 69.1 +/- 6.3%, respectively). However, for 57 patients treated with the latest intensive protocol, the 4-year DFS rate was much higher for the patients with TEL/AML1 fusion transcript than for those without it (100.0% v.s. 69.6 +/- 8.4%, respectively, p = 0.1472).


CONCLUSIONS
This study confirmed that TEL/AML1 gene fusion is the most common genetic event in pediatric ALL in Japan and is restricted to CD10-positive B-precursor ALL. Moreover, it was associated with an improved survival rate among patients treated with intensive therapy. Therefore, these data suggest that the patients with TEL/AML1 may not necessarily be candidates for less aggressive treatment.
Takahashi
Y
Y
Department of Pediatrics, Nagoya University School of Medicine, Japan.
Horibe
K
K
Kiyoi
H
H
Miyashita
Y
Y
Fukuda
M
M
Mori
H
H
Nozaki
C
C
Hasegawa
S
S
Kawabe
T
T
Kato
K
K
Kojima
S
S
Matuyama
T
T
Naoe
T
T
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D050676:Core Binding Factor Alpha 2 Subunit; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007223:Infant; D007564:Japan; D008297:Male; D009363:Neoplasm Proteins / Q000378:metabolism*; D015260:Neprilysin / Q000378:metabolism; D015514:Oncogene Proteins, Fusion; D016133:Polymerase Chain Reaction; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D014158:Transcription, Genetic; D000097764:ETS Translocation Variant 6 Protein
D050676:Core Binding Factor Alpha 2 Subunit; D009363:Neoplasm Proteins; D015260:Neprilysin; D015514:Oncogene Proteins, Fusion; C102421:TEL-AML1 fusion protein; D000097764:ETS Translocation Variant 6 Protein