MOLECULAR AND CYTOGENETIC ANALYSIS OF TRISOMY 12 AND TUMOR SUPPRESSOR GENES IN CHRONIC LYMPHATIC.LEUKEMIA

Abstract

In the present work karyotyping and FISH techniques were employed to detect the incidence of trisomy 12, Rb1 gene deletion and p53 gene deletion in 30 Egyptian B-ClL cases. These cases were of different Binet's stages (six patients were in stage A, thirteen patients were in stage B and eleven patients were in stage C). Karyotyping and FISH techniques were also carried out on three control subjects.

Peripheral blood or bone marrow lymphocytes of the three control subjects as well as the 30 B-ClL patients were cultured using Phytohemagglutinin and IL2 mitogens. This mitogen cocktail was used to stimulate malignant B- cells division. The three control subjects showed normal male (46 XY) and female

(46 XX) Karyotype.

In nllie out of thirty B-CLL cases (30%), no metaphases could be detected for karyotyping analysis. This mitotic failure occurred despite the use of the B-cell mitogens. Karyotyping was carried out on G-banded metaphase spreads of the remaining 21 B-CLL patients. Karyotyping revealed cytogenetic abnormalities in two CLL cases (6.67%); one case showed trisomy 12 and the other case showed a hemizygous deletion in the long arm of chromosome 13. These cytogenetic abnormalities were detected in about 20% of the examined metaphases. The two cases with cytogenetic abnormalities belonged to stage B of Binet's classification.