The analysis of chromosomal abnormalities in chronic lymphocytic leukemia is important at diagnosis, since it allows the identification of a malignant clone as well as helping in the differentiation of other lymphoproliferative disorders; at follow up, in order to permit the detection of additional abnormalities; in the therapeutic decision, since the presence of del(17p) means resistance to treatment; in treatment monitoring as it allows the detection of residual disease or the diagnosis of transformation (Richter’s transformation). Cytogenetics offers prognostic information and a better understanding of the disease. The analysis can be made by conventional G banding karyotyping, which detects around one third of abnormal cases or by FISH, which increases the rate of abnormality detection to 82%. FISH together with other prognostic criteria (mutation status, ZAP-70, etc) has allowed a better prognostication. The most frequent abnormalities are: trisomy 12 (+12), with a median survival of 9 years; translocation or deletion of 13q (t/del(13q)) with favorable prognosis and median survival of 11 years; deletion or translocation of 11q22-23, with 6.6 years of median survival; deletion of short arm of chromosome 17, del(17p), with median survival of 2.5 years; and deletion of 6q, translocation of 14q, giving a total of around 60% of the total abnormalities. Considering the importance of cytogenetics and prognostic information, every chronic lymphocytic leukemia patient should undergo FISH and karyotype evaluations, at diagnosis and during the follow up.
Chronic lymphocytic leukemia; cytogenetics; chromosomal abnormalities; FISH; trisomy 12; del(13q); del(11q); del(17p)
