Table 1.

Patient and sample characteristics

CharacteristicsNumber (%)
Median age, (range), y56 (9–75)
 Male16 (53.3%)
 Female14 (46.7%)
 ECD25 (83.3%)
 LCH5 (16.7%)
Sites of tissue biopsy, % of cohort (number of patients)a
 Bone11 (36.7%)
 Abdominal soft tissue (e.g., retroperitoneum)8 (26.7%)
 Skin6 (20.0%)
 Central nervous system5 (16.7%)
 Cardiac tissue2 (6.7%)
Median number of organ sites involved (range)
 ECD3 (0–11)
 LCHb2 (1–4)
Median number of prior treatments (range)c1 (0–4)
Tissue BRAFV600E genotype
 Mutant15 (50%)
 Wild-type6 (20%)
 Indeterminate (insufficient tissue or test failure)9 (30%)
Median number of urine collections (per patient, range)2 (1–8)
Median number of plasma collections per patient (range)1 (0–7)
Number of paired urine and plasma collections27 (90%)
Number of patients with initial sample acquired while off therapy26 (86.7%)
  • aSeveral individual patients underwent more than one biopsy.

  • bAll patients with LCH had multisystem disease with risk-organ involvement (11).

  • cRefers to the number of therapies before the first cfDNA analysis.