High-resolution comparative genomic hybridisation yields a high detection rate of chromosomal aberrations in childhood acute lymphoblastic leukaemia.
BACKGROUND
Cytogenetic aberrations are of prognostic significance in childhood acute lymphoblastic leukaemias and a high detection rate could improve the biological understanding and classification of these diseases.


METHODS
Bone-marrow samples from 92 children with acute lymphoblastic leukaemia were studied by high-resolution comparative genomic hybridisation (HRCGH) using dynamic standard reference intervals that enhance both specificity and sensitivity in the detection of aberrations.


RESULTS
In 80 patients (87%) HRCGH revealed a total of 405 aberrations, mostly whole chromosome gains (n = 265) and partial losses (n = 80). The 25 leukaemias with a gain of more than five whole chromosomes by HRCGH harboured only 7% of all losses. With G-band karyotyping 59 patients (64%) had aberrations. HRCGH revealed more aberrations per patient than did G-band karyotyping (median: 3 vs. 1, P = 0.005), revealed aberrations in 27 of the 34 patients for whom the G-band karyotyping failed or was found to be normal, and specifically revealed more 9p losses (21% vs. 5%, P < 0.005), 12p losses (12% vs. 2%, P < 0.05) and 17q gains (11% vs. 1%, P < 0.01). Compared to the present study, the frequency of patients with aberrant karyotypes was significantly lower in previous conventional CGH studies (64% vs. 87%, P < 0.0001), as was the rate of partial aberrations per patient (1.1% vs. 1.7, P < 0.001), particularly with fewer 6q losses, 9p losses and 17q gains detected.


CONCLUSIONS
HRCGH is superior to conventional CGH as an adjunct to G-band karyotyping as it detects recurrent aberrations at a significantly higher rate than both these techniques.
Kristensen
Tim D
TD
Department of Pediatrics, The University Hospital, Rigshospitalet, Copenhagen, Denmark.
Wesenberg
Finn
F
Jonsson
Olafur G
OG
Carlsen
Niels T
NT
Forestier
Erik
E
Kirchhoff
Maria
M
Lundsteen
Claes
C
Schmiegelow
Kjeld
K
D000293:Adolescent; D001853:Bone Marrow; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D005260:Female; D018628:Gene Dosage; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008297:Male; D009693:Nucleic Acid Hybridization; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D012015:Reference Standards; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity