ABSTRACT
Chronic lymphocytic leukemia (CLL) patients may acquire new chromosome abnormalities during the course of their disease. Clonal evolution (CE) has been detected by conventional chromosome banding (CBA), several groups also confirmed CE with fluorescence in situ hybridization (FISH). At present, there are minimal prospective data on CE frequency determined using a combination of both methods. Therefore, the aim of our study was to prospectively assess CE frequency using a combination of FISH and CBA after stimulation with CpG oligonucleotides and interleukin-2. Between 2008 and 2012, we enrolled 140 patients with previously untreated CLL in a prospective trial evaluating CE using FISH and CBA after stimulation. Patients provided baseline and regular follow-up peripheral blood samples for testing. There was a median of 3 cytogenetic examinations (using both methods) per patient. CE was detected in 15.7% (22/140) of patients using FISH, in 28.6% (40/140) using CBA, and in 34.3% (48/140) of patients by combining both methods. Poor-prognosis CE (new deletion 17p, new deletion 11q or new complex karyotype) was detected in 15% (21/140) of patients and was significantly associated with previous CLL treatment (p=0.013). CBA provides more complex information about cytogenetic abnormalities in CLL patients than FISH and confirms that many patients can acquire new abnormalities during the course of their disease in a relatively short time period.
Subject(s)
Chromosome Banding , Clonal Evolution , In Situ Hybridization, Fluorescence , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Adult , Aged , Female , Humans , Interleukin-2/pharmacology , Lymphocyte Activation/drug effects , Male , Middle Aged , Oligodeoxyribonucleotides/pharmacology , Prospective StudiesABSTRACT
The significance of chromosomal translocations (CTRAs) and karyotype complexity (KC) in chronic lymphocytic leukemia (CLL) remains uncertain. To gain insight into these issues, we evaluated a series of 1001 CLL cases with reliable classic cytogenetic data obtained within 6 months from diagnosis before any treatment. Overall, 320 cases were found to carry ≥ 1 CTRAs. The most frequent chromosome breakpoints were 13q, followed by 14q, 18q, 17q, and 17p; notably, CTRAs involving chromosome 13q showed a wide spectrum of translocation partners. KC (≥ 3 aberrations) was detected in 157 cases and significantly (P < 0.005) associated with unmutated IGHV genes and aberrations of chromosome 17p. Furthermore, it was identified as an independent prognostic factor for shorter time-to-first-treatment. CTRAs were assigned to two categories (i) CTRAs present in the context of KC, often with involvement of chromosome 17p aberrations, occurring mostly in CLL with unmutated IGHV genes; in such cases, we found that KC rather than the presence of CTRAs per se negatively impacts on survival; (ii) CTRAs in cases without KC, having limited if any impact on survival. On this evidence, we propose that all CTRAs in CLL are not equivalent but rather develop by different processes and are associated with distinct clonal behavior.
