Abstract
Introduction: Cytogenetic aberrations (CA) have emerged as important pathogenetic and prognostic factors in plasma cell disorders. However, in AL amyloidosis (AL) only a few reports with small numbers of patients have been published.
Methods: Using interphase FISH analysis in CD138+ cells, we evaluated the role of CA in a series of 85 AL patients as compared to 146 patients with a monoclonal gammopathy without treatment requirement in a prospective manner. Our panel included IgH translocations t(11;14), t(4;14), t(14;16) and translocation of 14q32 with an unidentified partner, gains of 1q21, 11q23 and 19q13 as well as deletions of 8p21, 13q14 and 17p13. Using these probes we could detect at least one of these aberrations in 95% of AL and in 88% of the control group. Age, gender and plasma cell content were statistically equally distributed among both groups.
Results: The most frequent aberration in AL was t(11;14), which was detected in 45% of AL patients as compared to 26% of the control group (p=0,056). It was strongly associated with the lack of an intact immunoglobulin (p<0,001), thus accounting for the frequent light chain only subtype in AL. Markedly, t(11;14) was more frequently found in combination with gain 11q23 in AL than in the control group (20% versus 6%, p = 0.005). Other frequent aberrations in AL included deletion 13q14 (32%) and gain 1q21 (21%), which were observed in the control group at comparable frequencies (34% and 20%). The overlapping character of the underlying plasma cell disorder in both disease entities was also emphasized by the similarities of branching patterns of the five major CA in cluster analysis applied in 169 patients (figure 1). The relation of clinical parameters and chromosomal aberrations was also evaluated. The analyzed CA had no impact on the organ involvement pattern in AL patients.
Conclusions: We observed a high frequency for t(11;14) in AL. Apart from this finding, the cytogenetic patterns known in monoclonal gammopathy of unknown significance and multiple myeloma were widely shared by AL amyloidosis.
Figure
