Background: Light chain amyloidosis is a rare plasma cell dyscrasia. Interphase fluorescence in situ hybridization (FISH) coupled to cytoplasmic staining of specific Ig (cIg-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 cIg-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 cIg-FISH, with the most common abnormalities being IgH translocations [48%]--including t(11;14) [39%], and t(14;16) [2%]--and del13/del13q [30%]. No t(4;14) or deletions of 17p (p53) were observed. Patients with t(11;14) had the lowest levels of clonal plasma cells, and those with del13 had the highest. The risk of death for patients harboring the t(11;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 cIg-FISH testing is important in patients with light chain amyloidosis and that t(11;14) is an adverse prognostic factor in these patients.