Mutational burden over time. (A) The percentage of tumor somatic variants detected in PBMC samples from in each individual at each time point sampled. The percentage was calculated for each individual as follows: (number of tumor-associated variants detected in PBMC genomic DNA collected at time point)/(total number of tumor-associated variants successfully resequenced using the PSTS probes)*100. (B) The number of putative ATL-driver variants identified in PBMC genomic DNA of each individual. (C) The frequency (copies per diploid genome) of the most abundant putative driver mutation detected in PBMC genomic DNA. Time zero indicates the time point at which each individual was diagnosed with ATL.