Establishment of an interlukin-6 independent variant (CMA-03/06) of the human myeloma cell line CMA-03 : biological molecular characterization by a genomic integrative analisys

Background Light chain amyloidosis is a rare plasma cell dyscrasia. Interphase fluorescence in situ hybridization (FISH) coupled to cytoplasmic staining of specific Ig (clg-FISH) on bone marrow plasma cells has become well established in the initial evaluation of multiple myeloma, a related disorder. Little, however, is known about cytogenetic abnormalities in patients with light chain amyloidosis. Design and Methods We reviewed 56 patients with light chain amyloidosis who had clg-FISH performed as part of their routine clinical testing using the standard screening panel employed in multiple myeloma at our institution. Results Seventy percent of patients had abnormal clg-FISH, with the most common abnormalities being IgH translocations [48%] - including t(ll;14) [39%], and t(14;16) [2%] - and dell3/dell3q [30%]. No t(4;14) or deletions of 17p (p53) were observed. Patients with t(ll;14) had the lowest levels of clonal plasma cells, and those with dell3 had the highest. The risk of death for patients harboring the t(ll;14) translocation was 2.1 (CI 1.04-6.4), which on multivariate analysis was independent of therapy. Conclusions Although preliminary, our data would suggest that clg-FISH testing is important in patients with light chain amyloidosis and that t(ll;14) is an adverse prognostic factor in these patients.