Trisomy 12 and t(14;18) in B-cell chronic lymphocytic leukemia

We report a case of B-cell chronic lymphocytic leukemia (B-CLL) in which trisomy 12 and t(14;18)(q32;q21) were simultaneously detected in the same leukemic clone. Southern blot analysis showed that the BCL2/IgJH rearrangement occurred at the major breakpoint region in the hot spot of the BCL2 gene. Double color fluorescence in situ hybridization analysis using multiple probes indicated that clonal B-cell with t(14;18) represented a subpopulation of the total leukemic cells and that trisomy 12 followed t(14;18) as the cytogenetic aberration in the development of B-CLL. Our findings suggests that both the t(14;18) and the trisomy are secondary chromosomal changes in the leukemogenesis of B-CLL.