MOLECULAR ANALYSIS OF A VARIANT 18-22 TRANSLOCATION IN A CASE OF LYMPHOCYTIC LYMPHOMA

We previously reported a 5' rearrangement of the BCL2 locus in a t(18;22) variant translocation found in a lymphocytic lymphoma. Primary structure analysis of both rearranged chromosomes confirmed the localization of the breakpoint in the so-called vcr region (for variant cluster region) that encompasses Z-DNA stretches 5' of the BCL2 locus, and in between Jlambda1 and Clambda1 segments on the IGL locus. A 1,027 nucleotide segment from chromosome 22 was repeated on both derivative chromosomes 18q + and 22q-. This segment contained an octanucleotide that was also present in the normal chromosome 18 close to the breakpoint. As a consequence of the translocation, a normal-sized BCL2 transcript was overexpressed in tumor cells.