Résumé
Objective To evaluate the predictive role of TEL/AML1 fusion gene in protocol CCLG-ALL-2008 and to identify relevant factors influencing the outcome of ALL with TEL/AML1 fusion gene. Methods Ninety-nine patients with ALL harboring TEL/AML1 fusion gene (positive) and 329 cases without any specific fusion genes (negative) at diagnosis of B-lineage ALL from June 2008 to December 2014 were enrolled and their clinical and biological features were analyzed. Following-up ended in October 2015, the survival status was calculated by K-M curve and prognostic factors were analyzed by COX model. Results There were no differences between the two groups in age, white blood cell at the diagnostic stage, and treatment responses at 4 time points, namely, prednisone good response on day 8, M3 status of BM on D15, and the minimal residual disease (MRD) more than 1.0×10-3 on day 33 and 12th week. During the follow-up period, the relapse rate was lower in the positive group than that in the negative group (14/99 vs 69/329), the mortality rate of the negative group was twice of that in the positive group (55/329 vs 8/99). The five-year overall survival (OS) rate, relapse-free survival (RFS) rate and event-free survival (EFS) rate of the positive group were (86.1 ± 4.9)%, (80.7 ± 5.1)% and (78.9 ± 5.1)%, respectively, and (79 ±2.8)%, (72± 3.1)%, and (69.6+ 3.1)% for the negative group as well. COX regression analysis indicated that relapse and MRD level at the 12th week were independent prognostic factors on OS, RFS, and EFS (P<0.05) for the two groups. Conclusions TEL/AML1 fusion gene could be regarded as a relatively good indicator of risks in ALL children treated by CCLG-ALL-2008 protocol. ALL patients with TEL/AML1 are recommended to receive more intensive therapy including hematopoietic stem cell transplantation when the patients were high level of MRD on the 12th week after treatment.
Résumé
Objective To detect expression of TEL-AML1 fusion genes in pediatric cases with acute lymphoblastic leukemia(ALL) and discuss the role of reverse transcriptase polymerase chain reaction(RT-PCR)and fluorescence in situ hybridization(FISH) in detection of t(12 ;21) and the clinical significance. Methods TEL-AML1 fusion gene was identified in bone marrow munonuclear cells from 31 newly diagnosed childhood ALL patients by NRT-PCR, FISH and conventional cytogenetic analysis (CCA). Results TEL-AML1 fusion gene was found in 7 out of 31 cases, accounting for 22.6 % in pediatric ALL, and 7 out of 31 cases accounting for 25.9 % in B-ALL Seven cases were found with t (12;21) by FISH and NRT-PCR. The incidence of the t(12;21) was 22.6 % in newly diagnosed pediatric ALLs. Conclusion It is concluded that TEL-AML1 rearrangement is a frequent molecular abnormality in childhood ALL. t(12;21) is the most common cytogenetic translocations in Chinese pediatric ALLs, but it is always difficult to identify by routine CCA.Other molecular methods, e.g. NRT-PCR and FISH are powerful in detecting such a critical genetic translocation.