CD56 expression and RAS mutations. The CD56 mean fluorescence was determined on CD38⁺⁺/CD45^-/i/CD19^- gated PCs from all MM and ExMM patients included in the study. MM patients were divided based on the RAS mutational status. For ExMM patients, the mean CD56 fluorescence for the major populations of aberrant BM-localized PCs is shown. Error bars represent the 90th and 10th percentiles. • indicates values above and below the 90th and 10th percentiles.