Abnormalities of Chromosomes 1p34-36, 4p16, 4q35, 9q11-32 and +7 Represent Novel Recurrent Cytogenetic Rearrangements in Chronic Lymphocytic Leukemia

Karyotypes were studied in over 250 cases of CLL seen at our Institution and 12 cases with a previously undescribed chromosome abnormality were identified. Cytogenetic and clinicobiological features in these patients are described. Fluorescence in situ hybridization using probes for the detection of +12 and deletions of 13q14, 17p13, and 11q22-23 was performed. Hematologic and clinical data were reviewed and a review of the literature was performed. Twelve patients were found carrying the following aberrations in the stemline: abnormalities at 1p34 (n = 2), 4p16 (n = 2), 4q35 (n = 2), 9q11-32 (n = 4) and +7 (n = 2). Trisomy 12 was found in 3 cases, whereas no case carried 13q-, 11q-, 17p-. Our data showed that (i) aberrations involving 1p34 and 4p16 as isolated chromosome anomalies were preferentially associated with early stage disease; (ii) 4q35 anomalies were associated with a relatively aggressive disease, atypical morphology and with monoclonal gammopathy; (iii) rearrangements of 9q were characterized by atypical morphology and aggressive disease with splenic involvement; (iv) +7 be may associated with +12. 1p34-36; 4p16; 4q35; 9q and chromosome 7 represent novel recurrent rearranged sites in CLL, with a 0.5-3% incidence. Transformation in these patients seemingly occured through a cytogenetic route not involving the classical CLL-associated chromosome regions. These chromosome rearrangements may be associated with peculiar hematologic features.