PTPRC and neoplasm: To better mimic the metastatic tumor formation of CTCs, we performed intracardiac injection of CT26-Vector or CT26-CD45 cells by limiting dilution (high gradient = 104 cells, medium gradient = 103 cells, and low gradient = 102 cells) into Balb/C mice and non-invasively monitored metastasis formation weekly by In Vivo Imaging System (Fig. 6e).