Abundance of the tumor-dominant HTLV-1 integration site in the peripheral blood. HTLV-1 integration sites were quantitatively mapped by linker-mediated (LM)-PCR followed by high-throughput sequencing. The OCI of each sample was computed (blue data points, plotted on the right y-axis). Pie charts also depict HTLV-1 integration sites at selected time points. Each slice of the pie represents a single unique HTLV-1 integration site, with the tumor-dominant integration site shown in red. LN indicates samples obtained from lymph node biopsies; all other samples are PBMCs. Results were corroborated by quantitative PCR for the tumor-dominant integration site (red data points, left y-axis) and expressed per 100 PBMCs (diploid cells). The PVL was also estimated by quantitative PCR for the Tax gene and expressed as copies per 100 PBMCs (black data points, left y-axis). Time zero indicates the time point at which each individual was diagnosed with ATL. Integration site data from 2 time points from patient A2 have been previously published in Gillet et al,⁹  and data from 3 time points from patient A1 have been previously published in Bangham et al.³²