TEL is frequently disrupted by chromosomal translocations such as the t(12;21), which is associated with nearly one-fourth of pediatric B cell acute lymphoblastic leukemia.
TEL gene status was determined for 926 patients with B-precursor ALL enrolled on the Pediatric Oncology Group ALinC 16 trials and patients were observed for a median time of 8 years.
A diagnosis of BCR-ABL1 (p190)-positive and ETV6-RUNX1-positive B-ALL was made, and treatment was initiated according to the AIEOP-BFM-ALL2000 protocol.
A diagnosis of BCR-ABL1 (p190)-positive and ETV6-RUNX1-positive B-ALL was made, and treatment was initiated according to the AIEOP-BFM-ALL2000 protocol.
Further investigation into the clinical and biological significance of elevated MN1 expression in TEL-AML1(positive) leukemia might provide insight into additional molecular mechanisms contributing to B-ALL and may lead to improved treatment options for patients.
Here we explore the clonal evolution of a form of childhood precursor-B cell acute lymphoblastic leukemia that is characterized by a chromosomal translocation generating a TEL-AML1 fusion gene.
However, this group was not representative as it included a high number of relapsed patients compared with the normal incidence in B-precursor ALL [54 in continuous complete remission (CCR) and 36 relapsed patients] and only a slightly better prognosis for TEL/AML1-positive patients was found (not significant) (four relapses in 17 TEL/AML1-positive patients vs. 32 relapses in 73 TEL/AML1-negative patients).
In this study, we examined the diagnostic (n = 77) and relapsed (n = 31) pediatric B-cell acute lymphoblastic leukemia (B-ALL) samples for the most common leukemia-associated gene variations CRLF2, JAK2, PAX5 and IL7R using deep sequencing and copy number alterations (CNAs) (CDKN2A/2B, PAX5, RB1, BTG1, ETV6, CSF2RA, IL3RA and CRLF2) by multiplex ligation proximity assay (MLPA), and evaluated for the clonal changes through relapse.
Persistence of TEL-AML1 fusion gene as minimal residual disease has no additive prognostic value in CD 10 positive B-acute lymphoblastic leukemia: a FISH study.
Regulated Pax5-Etv6 target genes identified in these B-ALLs encode proteins implicated in pre-B-cell receptor (BCR) signaling and migration/adhesion, which could contribute to the proliferation, survival, and tissue infiltration of leukemic B cells.
The TEL-AML1 fusion which results from the t(12;21) rearrangement in childhood B-precursor acute lymphoblastic leukaemia (B-precursor ALL) is often accompanied by loss of the untranslocated TEL allele.
The degree of anemia was significantly different for three distinct groups of patients compared to the remaining patients (mean hemoglobin; T-cell leukemia: 106 g/L versus 76 g/L (precursor B-cell acute lymphoblastic leukemia); within precursor B-cell ALL: TEL-AML1 positive: 68 g/L versus 79 g/L; BCR-ABL positive: 93 g/L versus 76 g/L; each p<0.05).
The IgH, TCR and TEL-AML1 markers can be used as targets by real-time PCR under the same cycling profile, allowing quantitation of MRD in more 95% of patients with pre-B ALL.
The most common rearrangement in childhood precursor B-cell acute lymphoblastic leukemia is the t(12;21)(p13;q22) translocation resulting in the ETV6-AML1 fusion gene.
The presence of the type A fusion transcript strongly implies ALL manifestation in ETV6/ABL1-positive hematologic malignancies as minor BCR breakpoint in BCR/ABL1-positive ALL.
The role of ETV6 in B-cell acute lymphoblastic leukemia (ALL) has been extensively studied, whereas only rare cases of ETV6 involvement in pediatric T-cell ALL have been described.
We show here that a t(9;12)(p24;p13) in a case of early pre-B acute lymphoid leukemia and a t(9;15;12)(p24;q15;p13) in atypical chronic myelogenous leukemia in transformation involve the ETV6 gene at 12p13 and the JAK2 gene at 9p24.