Deletion of chromosome 13 (band q14) but not trisomy 12 is a clonal event in B-chronic lymphocytic leukaemia (CLL).
Chromosomal abnormalities are detected by conventional cytogenetic or FISH analysis in 50% of chronic lymphocytic leukaemias (CLL). Trisomy 12 and del 13q14 account for 70% of these abnormalities. The incidence of these two abnormalities was studied in CLL patients by Southern blot analysis using a highly purified B-cell malignant population (CD5 > 95%, CD3 < 5%). Probes for the D13S25 marker on chromosome 13 band q14 and for the RBTN3 gene on chromosome 12 band p12-13, were used. Deletion of the D13S25 was detected in 17/42 patients (43%) in a homozygous (9.5%) or heterozygous (30%) configuration. Deletion of the D13S25 marker appears to be a clonal and early event in CLL development since it is detected in > 95% of the malignant clonal population. Conversely, trisomy 12 is rarely a clonal event (5/33 patients, 15%) and a varying proportion of cells carrying this abnormality can be demonstrated in 30% of CLL patients (10/33 patients).
Jabbar
S A
SA
Haematology Department, Royal Free Hospital School of Medicine, London.
Ganeshaguru
K
K
Wickremasinghe
R G
RG
Hoffbrand
A V
AV
Foroni
L
L
D015139:Blotting, Southern; D002872:Chromosome Deletion; D002881:Chromosomes, Human, Pair 12; D002882:Chromosomes, Human, Pair 13; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics*; D014314:Trisomy