PTPRC and colorectal carcinoma: As an initial evaluation of platform performance for CRC cells, HCT116 cancer cell lines were spiked both into PBS and 10x diluted blood from healthy donors to characterize capture efficiency and purity based on immunostaining for EpCAM (epithelial cell-surface marker), CD45 (a leukocyte cell-surface marker), and DAPI (a nuclear stain) (Figure 2C, Supplementary Figure S1).