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Table 2 CTCs per cohort and by time point, including CTC immune checkpoint biomarker expression for baseline

From: Expression of immune checkpoints on circulating tumor cells in men with metastatic prostate cancer

  mCRPC
pre-ARSI
mCRPC
post-ARSI
mHSPC
starting ADT
Total
EPCAM CTC Number per 7.5 mL whole blood (CellSearch)
Baseline CTCs N = 10 N = 10 N = 10 N = 30
 Mean (SD) 29.4 (55.2) 53.5(98.3) 16.6 (23.9) 33.2 (66.1)
 Median (range) 10.3 (0.3–181.0) 5.1(0.8–291.3) 3.1 (1.3–72.8) 4.3 (0.3–291.3)
  ≥ 5 CTCs 5 (50%) 5 (50%) 4 (40%) 14 (47%)
Week 12 CTCs N = 6 N = 4 N = 9 N = 19
 Mean (SD) 8.5 (16.0) 1.3 (0.9) 0.7 (0.8) 3.3 (9.2)
 Median (range) 0.9 (0.0–40.5) 1.0 (0.5–2.5) 0.0 (0.0–2.5) 0.8 (0.0–40.5)
  ≥ 5 CTCs 2 (33%) 0 (0%) 0 (0%) 2 (10%)
Disease progression CTCs N = 7 N = 6 N = 2 N = 15
 Mean (SD) 62.6 (125.6) 62.3 (94.0) 0.3 (0.4) 54.1 (101.9)
 Median (range) 20.8 (0.5–345.3) 28.4 (1.0–244.3) 0.3 (0.0–0.5) 3.3 (0.0–345.3)
  ≥ 5 CTCs 4 (57%) 3 (50%) 0 (0%) 7 (46%)
CTC immune checkpoint biomarker expression at baseline
PD-L1 Expression
   ≥ 1 CTC positive 6 (60%) 7 (70%) 4 (40%) 17 (57%)
   ≥ 50% CTCs positive 2 (20%) 3 (30%) 3 (30%) 8 (27%)
PD-L2 expression
   ≥ 1 CTC positive 4 (40%) 2 (20%) 4 (40%) 10 (33%)
   ≥ 50% CTCs positive 2 (20%) 2 (20%) 3 (30%) 7 (23%)
B7-H3 expression
   ≥ 1 CTC positive 8 (80%) 9 (90%) 9 (90%) 26 (87%)
   ≥ 50% CTCs positive 8 (80%) 9 (90%) 8 (80%) 25 (83%)
CTLA-4 expression
   ≥ 1 CTC positive 2 (20%) 1 (10%) 1 (10%) 4 (13%)
   ≥ 50% CTCs positive 1 (10%) 1 (10%) 1 (10%) 3 (10%)
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