Chromosome translocation t(16;21)(q24;q22)/RUNX1-RUNX1T3 is an infrequent but recurrent chromosomal abnormality identified in myeloid neoplasms, with only 25 cases have been reported to date.
Statistically significantly higher transcripts of the gene were detected in the acute lymphoblastic leukemia group as compared to the acute myeloid leukemia group, where AML1 overexpression appeared to associate with cytogenetic abnormalities additional to those that engage the AML1 gene, or that are reported as showing a "normal" karyotype.
The t(8;21) translocation is one of the most frequent cytogenetic abnormalities in acute myeloid leukaemia (AML) and results in the RUNX1/RUNX1T1 rearrangement.
The bone marrow cells in the present case also had a 5q deletion, and it was revealed that 5 out of the 8 reported cases (including the present case) with t(7;21)(p22;q22)/RUNX1-USP42 also had cytogenetic abnormalities of 5q.
In this issue of Blood,Matsuura and colleagues provide evidence that loss of GMCSF signaling promotes leukemic progression in association with one of the most frequently observed cytogenetic abnormalities in AML, the t(8;21)(q22;q22) that generates the RUNX1-ETO fusion protein.
Multivariate analysis incorporating age, white-cell count, and treatment parameters showed that six cytogenetic abnormalities (ETV6-RUNX1, high hyperdiploidy, iAMP21, t(9;22), loss of 13q, and abnormal 17p) retained their significance for effect on relapse risk.
Screening for the prognostically important chromosome abnormalities (TEL-AML1, BCR-ABL, E2A-PBX1, and MLL) using multiplex reverse-transcription polymerase chain reaction was performed on 299 consecutive patients with ALL at 3 study centers (236 de novo, 63 at relapse), with the ethnic composition predominantly Chinese (51.8%) and Malay (34.8%).
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.
Translocation of the ETO gene on human chromosome 8 with the AML1 gene on chromosome 21 (AML1-ETO) is a recurrent cytogenetic abnormality associated with approximately 12% of acute myelogenous leukemia (AML) cases.
In one case this chromosomal abnormality resulted in amplification of the AML1 gene (HUGO nomenclature: RUNX1), whereas in the other case the AML1 gene was not included in the tandem repetition, showing that apparently similar cytogenetic aberrations may be different at the molecular level.
The t(12;21)(p13;q22) translocation is the most common chromosomal abnormality yet identified in any pediatric leukemia and gives rise to the TEL-AML1 fusion product.
The t (12;21) was the commonest chromosomal anomaly detected in this population; 14 out of the 45 pediatric patients (31%) were positive for TEL/AML1 fusion, among which three had an additional derivative 21 [t (12;21)], four had a deletion of 12p and two had an extra copy of chromosome 21.
The translocation t(12;21)(p13;q22), which produces the TEL/AML1 fusion gene, is the most frequent chromosomal abnormality in patients with childhood acute lymphoblastic leukemia (ALL) and generally is associated with a favorable prognosis.
ETV6/AML1 fusion was found in nine out of 16 (56%) cases with a cytogenetically visible chromosome 12 abnormality, but also in nine out of 29 patients (31%) without a chromosome 12 abnormality or patients with failed cytogenetics (four out of 11 patients, 36%), making this the most common cytogenetic abnormality in childhood ALL.
A total of nine well-defined chromosome aberrations with fusion gene transcripts were selected: t(1;19) with E2A-PBX1, t(4;11) with MLL-AF4, t(8;21) with AML1-ETO, t(9;22) with BCR-ABL p190 and BCR-ABL p210, t(12;21) with TEL-AML1, t(15;17) with PML-RARA, inv (16) with CBFB-MYH11, and microdeletion 1p32 with SIL-TAL1.
The t(16;21)(q24;q22) translocation is a rare but recurrent chromosomal abnormality associated with therapy-related myeloid malignancies and a variant of the t(8;21) translocation in which the AML1 gene on chromosome 21 is rearranged.
However, using fluorescence in situ hybridization (FISH) and by screening for the TEL/AML1 rearrangement by the polymerase chain reaction (PCR), it has been demonstrated to be the most frequent known structural chromosomal abnormality in childhood acute lymphoblastic leukemia (ALL).
The t(12;21) is a recurring chromosomal abnormality in acute lymphoblastic leukaemias (ALLs) which results in the production of an ETV6-AML1 fusion gene.