PECAM1 and neoplasm: Cells negative for vascular endothelial cell and leukocyte biomarkers (CD31- CD45-) and with positive expression of tumor biomarkers (HE4+ or CA125+) or chromosome 8 aneuploidy were defined as CTCs of ovarian cancer (DAPI+/CD45-/CD31-/HE4+ or CA125+, or DAPI+/CD45-/CD31- with aneuploidy of chromosome 8) (Figure 2A) (manuscript submitted).