Suprisingly, high expression of the hsa-mir-125b-2 cluster, consisting of three miRNAs, was identified in leukemias with the structural ETV6/RUNX1 abnormality and not in ALLs with trisomy 21.
Three patients showed extra copies of chromosome 21 including a case in which the trisomy 21 (+21) clone was distinct from the one harboring TEL/AML1 gene fusion.
We present a unique case with a carrier patient of a constitutional ring chromosome 21 (partial monosomy and trisomy 21) with dysmorphic features and congenital malformations phenotype, who developed acute myeloid leukaemia with myelodysplasia-related changes and two ring 21 chromosomes with RUNX1 amplification.
As expected, the most strongly associated SNP was the APOE ɛ4 rs429358 variant (HR=2.47 [1.58, 3.87], p=7.52×10(-5)), although variants within the more recently implicated SORL1 and RUNX1 genes were also strongly associated with DAD in DS (HR=0.54 [0.37, 0.80], p=0.002 and HR=1.61 [1.15, 2.26], p=0.006 respectively).
High incidence of the ETV6/RUNX1 fusion gene in paediatric precursor B-cell acute lymphoblastic leukaemias with trisomy 21 as the sole cytogenetic change: a Nordic series of cases diagnosed 1989-2005.
Since the RUNX1 gene contributes to megakaryopoiesis and acquired trisomy 21 is the most frequent numerical chromosome anomaly in acute megakaryoblastic leukemia (AMLK), a systematic study of RUNX1 abnormalities was performed by fluorescence in situ hybridization in AMLK patients.
The genetic changes with especially large discrepancy rates at diagnosis were del(7q) (20.0%), PML/RARA (17.6%), and trisomy 21 (12.5%) and, at follow-up, BCR/ABL (28.2%) and AML1/ETO (24.4%); the latter two showed only small discrepancies at diagnosis (4.7 and 4.8%, respectively).
Short hairpin RNA knockdown of RUNX1 in a non-DS AMkL cell line, Meg-01, resulted in significantly increased sensitivity to cytosine arabinoside, accompanied by significantly decreased expression of PIK3CD, which encodes the delta catalytic subunit of the survival kinase, phosphoinositide 3 (PI3)-kinase.
BACH1 was significantly overexpressed in fetal DS (p < 0.008) as compared to controls whereas RUNX1 and ERG proteins were comparable between groups, and SIM2 l was not detectable in any specimen.
High incidence of biallelic point mutations in the Runt domain of the AML1/PEBP2 alpha B gene in Mo acute myeloid leukemia and in myeloid malignancies with acquired trisomy 21.
Thus, our data indicate that physical interaction and synergy between GATA1 and RUNX1 are retained in DS-AMKL, although it is still possible that increased RUNX1 activity plays a role in the development of leukemia in DS.
Somatic mutations in RUNX1 are preferentially detected in acute myeloid leukemia (AML) M0, myeloid malignancies with acquired trisomy 21, and certain myelodysplastic syndrome (MDS) cases.
Thus, it was somewhat surprising that according to the currently available literature the incidence of TEL/AML1+ BCP ALL is extremely low in patients with Down syndrome (DS).
This mouse model may be useful for analysing the pathogenesis of myeloid leukemias with RUNX1 overdose, especially to examine whether an extra-copy of RUNX1 by trisomy 21 is causally related to Down's syndrome-related acute megakaryoblastic leukemia (DS-AMKL).
Thus, it was somewhat surprising that according to the currently available literature the incidence of TEL/AML1+ BCP ALL is extremely low in patients with Down syndrome (DS).
RUNX1 is essential for differentiation of blood cells, especially B cells; thus, hypermethylation of the RUNX1 promoter in B-cell precursors might be associated with increased incidence of B-cell precursor ALL in DS patients.