Dicentric (17;18) in a case of atypical B-cell chronic lymphocytic leukemia

We report a new dic(17;18)(p11.2;p11.2) in a 61-year-old male patient diagn osed with atypical B-cell chronic lymphocytic leukemia. The dic(17;18)(p11. 2;p11.2) was detected in 90%, 10%, and 100% of metaphases in the peripheral blood, bone marrow and lymph node, respectively. Fluorescence in situ hybr idization studies with chromosome 17 and 18 centromeric probes revealed the presence of two normal centromeres of both chromosomes 17 and 18. The cent romere of one chromosome 17 was found together with the centromere of one c hromosome 18, confirming the dicentric nature of the rearrangement. In addi tion, with the use of a 17p13.1 region probe, monosomy of the 17p13 region, where the Tp53 gene is located, was observed. (C) 2000 Elsevier Science In c. All rights reserved.