We assessed CD138-purified plasma cell samples from 196 AL-amyloidosis, 62 MGUS, 259 asymptomatic, 764 symptomatic, and 90 relapsed myeloma patients, including longitudinal pairs of asymptomatic/symptomatic (n = 34) and symptomatic/relapsed myeloma (n = 57) regarding interphase fluorescence in situ hybridization (n = 1,380), CD38-expression by gene expression profiling (n = 1,371), RNA-sequencing (n = 593), and flow cytometry (n = 800). Here, CD38 is linked to AL amyloidosis.