Cytogenetic intraclonal heterogeneity of plasma cell dyscrasia in AL amyloidosis as compared with multiple myeloma

Abstract

Analysis of intraclonal heterogeneity has yielded insights into the clonal evolution of hematologic malignancies. We compared the clonal and subclonal compositions of the underlying plasma cell dyscrasia in 544 systemic light chain amyloidosis (PC-AL) patients with 519 patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), or symptomatic MM; ie, PC-non-AL patients). Using interphase fluorescence in situ hybridization, subclones were stringently defined as clone size below two thirds of the largest clone and an absolute difference of ≥30%. Subclones were found less frequently in the PC-AL group, at 199 (36.6%) of 544 as compared with 267 (51.4%) of 519 in the PC-non-AL group (P