The <i>ERG</i> risk genotype was underrepresented in ALL with the <i>ETV6-RUNX1</i> fusion (<i>P</i> < .0005) but enriched in the <i>TCF3-PBX1</i> subtype (<i>P</i> < .05).
This study was aimed to explore the METTL3 and METTL14 expressions in children with ETV6/RUNX1(E/R)-positive acute lymphoblastic leukemia (ALL) and investigate the relation between the METTL3 and METTL14 expressions with clinical features.
Common CNAs involved CDKN2A/2B (30.3%), IKZF1 (27.3%), PAX5 (9.1%), RB1 (9.1%), BTG1 (6.7%), and ETV6 (6.7%), which regulate cell cycle, B lymphopoiesis, or act as tumor suppressors in ALL.
Three out of 57 patients (5.3%) harbored confirmed germline mutations that were likely causal, in NBN, ETV6, and FLT3, with an additional six patients (10.5%) harboring putative predisposing mutations that were rare in unselected individuals (<0.01% allele frequency in the Exome Aggregation Consortium, ExAC) and predicted functional (scaled CADD score ≥ 20) in known or potential ALL predisposition genes (SH2B3, CREBBP, PMS2, MLL, ABL1, and MYH9).
A high proportion of ETV6-RUNX1-positive ALL relapses (40%) in our cohort showed a poor response to induction treatment at relapse, and therefore had an indication for hematopoietic stem cell transplantation, demonstrating the need of accurate identification of this subgroup.
NRAS mutations were associated with a higher frequency of hyperdiploidy (P = 0.01) and lower frequency of ETV6-RUNX1 (P < 0.01), whereas KRAS mutations were associated with younger age (P < 0.01), a higher frequency of KMT2A rearranged (P < 0.01) but no significant difference if infants with ALL were excluded, and inferior event-free survival (66.6% vs. 80.5%, P = 0.04).
Phosphatase of regenerating liver-3 <i>(PRL-3/PTP4A3)</i> is upregulated in multiple cancers, including BCR-ABL1- and ETV6-RUNX-positive acute lymphoblastic leukemia (ALL).
Notably, the t(12;21) translocation leading to an ETV6-AML1 fusion gene is the most common genetic alteration found in childhood acute lymphoblastic leukemia.
The multiplex ligation-dependent probe amplification (MLPA) method was used to detect the copy number alterations (CNAs) of IKAROS family zinc finger 1 (<i>IKZF1</i>), paired box 5 (<i>PAX5</i>), ETS variant 6 (<i>ETV6</i>), RB transcriptional corepressor 1 (<i>RB1</i>), BTG anti-proliferation factor 1 (<i>BTG1</i>), early B-cell factor 1 (<i>EBF1</i>), cyclin dependent kinase inhibitor 2A/2B (<i>CDKN2A/2B</i>) and cytokine receptor like factor 2 (<i>CRLF2</i>) genes in 87 adults with acute lymphoblastic leukemia (ALL) in China.
Patients with t(12;21)/(ETV6-RUNX1) or hyperdiploidy >50 ALL had the best prognosis; those with a negative MRD on day 19 had a particularly low risk of relapse: 1.9% and 3.8%, respectively.
The t(12;21) (p13;q22) chromosomal translocation resulting in the <i>ETV6/RUNX1</i> fusion gene is the most frequent structural cytogenetic abnormality in children with acute lymphoblastic leukemia (ALL).
In conclusion, we show that ETV6/RUNX1-like ALL is associated with CD27<sup>pos</sup> /CD44<sup>low-neg</sup> immunophenotype and identify ARPP21 deletions to contribute to its specific genomic profile enriched for ETV6 and IKZF1 lesions.
<i>ETV6/RUNX1</i> (+) ALL may be heterogeneous in terms of prognosis, and variables such as MRD at end ofremission induction or additional structural abnormalities of 12p could define a subset of patients who are likely to have poor outcome.
The relapse samples retained the translocation of ETV6-RUNX1 relative to the three-way translocation t(8;12;21) at diagnosis, suggesting that the three-way translocation might be an important risk factor for relapse in patients with ETV6-RUNX1-positive ALL and should be further studied.
We have recently reported that ETV6/RUNX1 transcript is a target of RNA-binding protein IGF2BP1 in t(12;21)(p13;q22)-positive ALL suggesting a direct role of IGF2BP1 in ETV6/RUNX1-mediated leukemogenesis.
These data infer that IGF2BP1 is a potent regulator of ETV6/RUNX1 mRNA stability and potentially link this evolutionary-highly conserved protein to cell transformation events in ETV6/RUNX1-mediated leukemogenesis of t(12;21)(p13;q22)-positive ALL.
We reasoned that shared clonal rearrangements of IG or TCR genes by concordant ALL in twins would be informative about the fetal cell type in which clonal advantage is elicited by ETV6-RUNX1.