Figure 1.

Somatic alterations detected in plasma cell-free DNA. A) Schematic showing the proportion of cell-free DNA that was tumor derived (the circulating cell-free tumor DNA [ctDNA] fraction) and the relationship of this variable to select clinical characteristics. The grid provides an overview of metastatic locations in each patient at the time of sampling (green), with filled black circles indicating the region that was subjected to tissue biopsy concomitant to plasma collection. Orange squares denote prior exposure to (and progression on) three major systemic therapies for metastatic castration-resistant prostate cancer (mCRPC) at the time of paired sample collection. B) Matrix of mutations and copy number alterations detected in independent analysis of plasma cell-free DNA (cfDNA) samples. All 72 mCRPC driver genes included in the cfDNA sequencing panel are shown (sorted by chromosome and position). Note that sensitivity of copy number calling is diminished in samples with less than 35% ctDNA. ALP = alkaline phosphatase; cfDNA = cell–free DNA; ctDNA = circulating cell-free tumor DNA; LN = lymph node; PSA = prostate-specific antigen.