Genomic characterization implicates iAMP21 as a primary genetic event in childhood B-cell precursor acute lymphoblastic leukaemia

ABSTRACT: Intrachromosomal amplification of chromosome 21 (iAMP21) defines a distinct subgroup of childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) shown to have a dismal outcome on standard therapy. For improved diagnosis and prognosis of these patients, the initiating genetic events need to be elucidated. To investigate the genetic basis, the genomes of 94 iAMP21 patients were interrogated by genomic arrays, FISH and MLPA. Detailed mapping of chromosome 21 refined the common region of amplification (CRA) to 5.1 Mb; including the RUNX1 gene, miR-802 and genes mapping to the Down Syndrome Critical Region. Over a quarter of copy number alterations targeted chromosome 21, including telomeric deletions in 88% of patients. Global analysis by genomic arrays identified recurrent abnormalities affecting genes in key pathways. The frequency of these abnormalities were determined by FISH and/or MLPA; IKZF1 (22%), CDKN2A/B (17%), PAX5 (8%), ETV6 (19%) and RB1 (37%). Study of the clonal architecture provided evidence that these abnormalities, and P2RY8-CRLF2, were secondary to chromosome 21 instability. This study provides convincing evidence that chromosome 21 instability is the only abnormality common to all iAMP21 patients and the initiating event is likely hidden within the complex structural rearrangements of this abnormal chromosome. DNA copy number analysis of 17 diagnostic and 1 relapse acute lymphoblastic leukaemia samples was performed using agilent 185K microarrays. These samples were hybridised against gender matched reference DNA.

ORGANISM(S): Homo sapiens

SUBMITTER: Vikki Rand 

PROVIDER: E-GEOD-26192 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress