We analyzed the TS-2 acute lymphoblastic leukemia (ALL) cell line that contains a t(1;19)(q23;p13.3) but lacks E2A-PBX1 fusion typically present in leukemias with this translocation.
Our results have important implications for the detection of residual disease in pediatric patients where expression of the typical E2A/PBX1 mRNA may occur both in cig+ (pre-B) and cig- (early pre-B) immunologic subtypes of ALL.
This study was conducted to determine the frequency of common fusion transcripts BCR-ABL, TEL-AML1, MLL-AF4 and E2A-PBX1 for B-ALL and SIL-TAL1 for T-ALL as seen at a tertiary care center in India.
Maximal specificity is presumably achieved when the DNA sequences amplified are truly leukaemia-specific, such as BCR/ABL in chronic myelogenous leukemia, RARA PML/RARA in t(15;17) acute myelogenous leukemia, DEK/CAN in t(6;9) AML, PBX1/E2A in t(1;19) acute lymphoblastic leukemia (ALL), or TAL-1 deletions in other T-ALLs.
TCF3 rearrangement mostly t(1;19) (q23;p13)/ TCF3-PBX1 gene is associated with favorable outcome in acute lymphoblastic leukemia (ALL) upon treatment with intensification protocols; however, it is associated with higher incidence of central nervous system (CNS) relapse which may affect outcome of patients.
The E2A/PBX1 and the BCR/ABL fusion genes result from the t(1;19)(q23;p13) and the t(9;22)(q34;q11), respectively, and encode oncoproteins which are thought to play an important role in the development of acute lymphoblastic leukemia (ALL) subtypes associated with adverse prognosis.
The 68 black children were significantly more likely than the 338 white children to have higher-risk prognostic features, including an initial leukocyte count greater than 100 x 10(3)/ microL, a T-cell immunophenotype, and the t(1;19) chromosomal translocation with E2A-PBX1 fusion, and were less likely to have hyperdiploid blast cells, a favorable prognostic factor in childhood ALL.
Aberrant expression of tumor suppressor genes WT 1, RB 1, p53, homozygous deletion of p16 gene and their relationship with expression of oncogenes BCR-ABL, TEL-AML 1, MLL-AF 4, E2A-PBX 1, SIL-TAL 1 were determined in bone marrow samples of children with de novo B-lineage (n=170) and T-lineage (n=25) acute lymphoblastic leukemia (ALL).
Of 11 cases of cIg+ ALL with the t(1;19), 10 had E2A-pbx1 chimeric transcripts with identical junctions and a characteristic set of E2A-Pbx1 hybrid proteins.
In this study, we developed a multiplex RT-PCR assay for detection of the 4 most frequent translocations in ALL (BCR-ABL, TEL-AML1, MLL-AF4, and E2A- PBX1).
SETDB2 expression is maintained as a direct target gene of the chimeric transcription factor E2A-PBX1 in a subset of ALL and suppresses expression of the cell-cycle inhibitor CDKN2C through histone H3K9 tri-methylation, thus establishing an oncogenic pathway subordinate to E2A-PBX1 that silences a major tumor suppressor in ALL.
In this cohort of Taiwanese children, the relative frequencies of the 4 translocations of B-lineage ALL were 8% with ALL-type t(9;22)/BCR-ABL1, 4% with (1;19)/TCF-PBX1, 2% with t(4;11)/MLL-AF4, and 17.6% with t(12;21)/ETV6-RUNX1.
The (1;19)(q23;p13) translocation, leading to the production of the E2A/PBX1 fusion transcript, is one of the most common translocations in pediatric B-lineage acute lymphoblastic leukemia (ALL).
In ALL, ZAP-70 expression is associated with the E2A/PBX1 rearrangement and pre-B stage and may have a prognostic role and be a candidate molecule for targeted therapies.
The chromosomal translocation t(1;19)(q23;p13) and its variant form der(19)t(1;19) found in 3-5% of acute lymphoblastic leukemia (ALL) results in the expression of the E2A-PBX1 fusion transcript.
Using an integrated approach, we uncovered distinct mutation, gene expression and drug response profiles in TCF3-HLF-positive and treatment-responsive TCF3-PBX1-positive ALL.
No difference was observed in the expression of MyAg between patients with normal or abnormal cytogenetics or between those with high-risk (BCR-ABL+, ALL1-AF4+, E2A-PBX1+) or low-risk B-lineage ALL.
We found significantly lower expression of the reduced folate carrier (SLC19A1, an MTX uptake transporter) in E2A-PBX1ALL, significantly higher expression of breast cancer resistance protein (ABCG2, an MTX efflux transporter) in TEL-AML1 ALL, and lower expression of FPGS (which catalyzes formation of MTXPG) in T-lineage ALL, consistent with lower MTXPG accumulation in these ALL subtypes.