Trisomy 12 in B-cell chronic lymphocytic leukaemia: assessment of lineage restriction by simultaneous analysis of immunophenotype and genotype in interphase cells by fluorescence in situ hybridization.
We have studied the lineage restriction of trisomy 12 in six patients with B-cell chronic lymphocytic leukaemia (CLL) by simultaneous analysis of immunophenotype and fluorescence in situ hybridization (FISH) signals in single interphase cells. Fresh uncultured cells from each patient were immunophenotyped by the alkaline phosphatase anti-alkaline phosphatase method (APAAP) using monoclonal or polyclonal antibodies and hybridized with a chromosome 12 specific alpha-satellite DNA probe. In all cases trisomy 12 was restricted to the clonal B-cells, kappa positive or lambda positive, whereas T-cells (CD3 positive) and non clonal B-cells had only two chromosome 12 signals. Within the clonal B-cell population a large proportion of cells were disomic for chromosome 12, whilst trisomic cells ranged from 21% to 37%. The absence of trisomy 12 in T-cells and the mosaicism demonstrated in the clonal B-cells suggests that this abnormality is a secondary event during the leukaemic transformation of CLL and develops in an already established neoplastic B-cell population.
Garcìa-Marco
J
J
Academic Department of Haematology and Cytogenetics, Royal Marsden Hospital, London.
Matutes
E
E
Morilla
R
R
Ellis
J
J
Oscier
D
D
Fantes
J
J
Catovsky
D
D
Price
C M
CM
D000368:Aged; D002881:Chromosomes, Human, Pair 12; D005260:Female; D005838:Genotype; D006801:Humans; D007124:Immunoenzyme Techniques; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase / Q000235:genetics; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics*; D008297:Male; D014411:Neoplastic Stem Cells / Q000473:pathology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014314:Trisomy; D014407:Tumor Cells, Cultured
D013755:Tetradecanoylphorbol Acetate