A plasma cell leukemia patient showing bialleic 14q translocations: t(2;14) and t(11;14)

We report here an IgG/lambda-type plasma cell leukemia patient showing bial leic 14q32 translocations. All immunoglobulins were suppressed in this pati ent, but a small amount of monoclonal IgG was detected by immunoelectrophor esis. Two cells of six peripheral blood mononuclear cells showed 46,XY,t(2; 14)(q11;q32), i(8)(q10), t(11;14)(q13;q32), del(12)(q13.1) by karyotypic an alysis. We confirmed the juxtaposition of IgH and PRAD1/Cyclin D1 genes by fluorescent in situ hybridization and overexpression of the PRAD1/Cyclin D1 gene, but Southern analysis showed no bcl-1 rearrangement. We analyzed the t(2;14)(q11;q32) using DNA fragments derived from childhood B-chronic lymp hocytic leukemia cases bearing t(2;14)(p13;q32). Southern and Northern anal yses demonstrated no alteration of these genes, indicating that this t(2;14 ) was different from that of childhood B-chronic lymphocytic leukemia. At t he IgH loci, Southern analysis showed two rearranged bands and one germline band of JH. C mu was deleted on one rearranged allele but remained on the other, suggesting that the chromosome translocation occurred after producti ve class switch recombination on the C mu deleted allele.