Clonal evolution after short-term treatment with lenalidomide. Results from 6 responders (A) and 6 nonresponders (B) are shown. Other results from 30 additional patients are available in supplemental Figure 2. Paired BM mononuclear cell samples (n = 42) were collected for genotyping before and after 4 cycles of treatment expressed in months of follow-up. Depth at the variant position was considered to calculate variant allele frequency and its 95% CI. For each patient, variant allele frequencies of a given mutation were compared between 2 consecutive time points of the follow-up period using Fisher’s exact test. Left: dot representation; closed symbols represent major mutations and open symbols represent minor mutations for each patient. Vertical bars represent 95% CIs. Right: radar plots of the variant allele frequencies at inclusion and after 4 cycles of treatment. Maximum scale value is 50%, with intervals of 10%. Each extremity of the spider web represents 1 mutation. Gray lines indicate the variant allele frequencies at inclusion and black lines indicate the variant allele frequencies after treatment. In both panels, significant differences between the 2 time points are indicated. *P < .05; **P < .01; ***P < .001. UPN, unique patient number.