Effect of chemotherapy regimen CCLG-ALL-2008 on children with TEL/AML1 fusion gene positive of acute lymphoblastic leukemia / 临床儿科杂志

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.

Evolução clínica e fusão TEL/AML1 em pacientes pediátricos com síndrome de Down e leucemia linfoblástica aguda / Clinical evolution and TEL/AML1 fusion in pediatric patients with Down syndrome and acute lymphoblastic leukemia

O risco aumentado de desenvolvimento de leucemia apresentado pelos indivíduos portadores de síndrome de Down (SD) já é bem conhecido. Entretanto, a contribuição do cromossomo 21 extraconstitucional ao processo de leucemogênese, ainda não está bem estabelecida. A fusão TEL/AML1 é a anomalia estrutural mais frequentemente encontrada em leucemia linfoblástica aguda (LLA) da infância, mas a sua associação com a LLA em pacientes com SD não é bem clara. Nós investigamos uma amostra de quatro pacientes com LLA e SD (LLA-SD) quanto à sua evolução clínica e seus aspectos citogenéticos, inclusive com pesquisa da fusão TEL/AML1. A idade do diagnóstico variou de 5 anos e 7 meses a 13 anos e 7 meses, o número de leucócitos em sangue periférico de 7.200 a 208.000/mm³ e a porcentagem de blastos na medula óssea de 20 por cento a 95 por cento. Apenas um paciente foi positivo para a fusão TEL/AML1. Todos os pacientes entraram em remissão completa e nenhum apresentou comprometimento extramedular ou recidiva. O tempo de sobrevida variou de 67 a 82 meses e não ocorreu nenhum óbito. Em nossa série de crianças com LLA-SD, os aspectos citogenéticos e a boa evolução clínica observados estão de acordo com o relatado na literatura.

The increased risk of developing leukemia found in Down syndrome (DS) patients is already well-known. However, the contribution of the extra copy of chromosome 21 to this leukemogenesis is still not well established. The TEL/AML1 fusion is the most frequently found structural anomaly in acute lymphoblastic leukemia (ALL) in childhood, but its association with ALL in DS patients is not very clear. We investigated a sample of four patients with ALL and DS (ALL-DS) in terms of their clinical evolution and cytogenetic aspects, including a study of the TEL/AML1 fusion. The ages of the patients ranged from 5 years and 7 months to 13 years and 7 months, the number of leukocytes in peripheral blood was 7,200 to 208,000 x 106 and the percentage of blasts in the bone marrow was 20 to 95 percent. Only one patient tested positive for the TEL/AML1 fusion. All patients achieved complete remission and none presented extramedullary involvement or relapse. The survival period ranged from 67 to 82 months and there was no death. In our series of children with ALL-DS, the cytogenetic aspects and the good clinical evolution observed are in agreement with the literature.

Identification of TEL-AML1 fusion gene in childhood acute lymphoblastic leukemia / 白血病·淋巴瘤

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.

TEL/AML1 Fusion Transcripts in Childhood B-Lineage Acute Lymphoblastic Leukemia / 대한혈액학회지

BACKGROUND: The t(12;21)(p13;q22), which fuses the TEL gene on chromosome 12p13 and the AML1 gene on chromosome 21q22, is observed in approximately 20~25% of childhood B-lineage acute lymphoblastic leukemia (ALL) cases and is associated with a favorable outcome. A retrospective study was conducted to investigate the frequency of TEL/AML1 fusion in the patients diagnosed as childhood B-precursor ALL. METHODS: Because of the low detection rate by routine karyotypic analysis, we studied 54 children with B-lineage ALL using the fluorescence in situ hybridization (FISH) analysis. RESULTS: Results of this analysis demonstrated a 9.3% frequency of TEL/AML1 fusion, relatively lower than Japanese, Taiwanese and Caucasian children. All five patients with TEL/AML1 fusion showed CD10 positivity and predominance of male patients (4:1). Two cases of TEL/AML1 positive groups expressed the myeloid antigens, but no significance was noted (P>0.05). In TEL/AML1 positive groups, the leukemia was developed between 4 and 5 years old age (favorable age) and showed low initial leukocyte counts (<50,000/micro L). CONCLUSION: Although these findings combined with earlier reports indicate that TEL/ AML1 fusion was frequent genetic abnormality in childhood ALL, relatively low frequency in Korean patients suggested the existence of geographic or racial variations in the genotype of ALL.