Characterisation of dic(9;20)(p11-13;q11) in childhood B-cell precursor acute lymphoblastic leukaemia by tiling resolution array-based comparative genomic hybridisation reveals clustered breakpoints at 9p13.2 and 20q11.2.
Although the dic(9;20)(p11-13;q11) is a recurrent chromosomal abnormality in paediatric B-cell precursor acute lymphoblastic leukaemia (BCP ALL), occurring in approximately 2% of the cases, its molecular genetic consequences have not been elucidated. In the present study, high-resolution genome-wide array-based comparative genomic hybridisation (array-CGH) and fluorescence in situ hybridisation (FISH) were used to characterise the 9p and 20q breakpoints (BPs) in seven childhood BCP ALLs with dic(9;20), which was shown to be unbalanced in all of them, resulting in loss of 9p13.2-pter. Five of the cases had loss of 20q11.2-qter, whereas two displayed gain of 20cen-pter. All BPs on 9p clustered in a 1.5 Mb segment of the sub-band 9p13.2; in three of the cases, the 20q BPs mapped to three adjacent clones covering a distance of 350 kb at 20q11.2. Thus, the aberration should be designated dic(9;20)(p13.2;q11.2). One of the ALLs, shown to have a complex dic(9;20), was further investigated by FISH, revealing a rearrangement of the haemapoietic cell kinase isoform p61 (HCK) gene at 20q11. The disruption of HCK may result in a fusion gene or in loss of function. Unfortunately, lack of material precluded further analyses of HCK. Thus, it remains to be elucidated whether dic(9;20)(p13.2;q11.2) leads to a chimaeric gene or whether the functionally important outcome is loss of 9p and 20q material.
Schoumans
Jacqueline
J
Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden. jacqueline.schoumans@ki.se
Johansson
Bertil
B
Corcoran
Martin
M
Kuchinskaya
Ekaterina
E
Golovleva
Irina
I
Grandér
Dan
D
Forestier
Erik
E
Staaf
Johan
J
Borg
Ake
A
Gustafsson
Britt
B
Blennow
Elisabeth
E
Nordgren
Ann
A
D000293:Adolescent; D002051:Burkitt Lymphoma / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002872:Chromosome Deletion; D002874:Chromosome Mapping / Q000379:methods; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics*; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D007223:Infant; D007621:Karyotyping; D008297:Male; D009693:Nucleic Acid Hybridization / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods
D004273:DNA, Neoplasm