Genetic abnormalities and clinical outcome in chronic lymphocytic leukemia

Abstract

B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in the elderly population. Under conventional cytogenetic (CC) analysis, approximately 50% of CLL cases show clonal aberrations. Using fluorescent in situ hybridization (FISH), the percentage of patients with abnormalities rises to almost 80%, the most frequent being 13q14, ATM, and TP53 deletions and trisomy 12. The aim of this study was to establish the incidence of genetic changes in B-CLL patients using CC and FISH and to evaluate the prognostic implications. Of the 65 patients analyzed, genetic aberrations were found in 36.7% with CC and in 68.4% with FISH. The frequencies of abnormalities were as follows: 13q deletion, 42.1%; trisomy 12, 19.2%; ATM deletion, 17.5%; and TP53 deletion, 8.7%. Significant differences were observed when the overall survival was correlated with Rai stage (P = 0.000). FISH abnormalities were correlated with age, sex, morphology, white blood cell count, CD38 expression, Rai stage, disease status, and survival. Significant differences were obtained with age (P = 0.05) and disease status (P = 0.01). Deletion of 13q was the most frequent abnormality (36.6%) among old patients (> or =60); trisomy 12 was the most frequent (31.3%) in younger patients (<60). Half of the patients with stable disease showed 13q deletion, and the most frequent abnormality in patients with progressive disease was ATM deletion (22.2%).