Conversely, negative selection assays generally remove white blood cells (WBCs) from blood samples by targeting leukocyte surface-specific antigens (e.g., CD45 and CD61) that are not expressed in CTCs to achieve GC- and CRC-CTCs enrichment; the kits and techniques include the EasySep® Human CD45 Depletion Kit (34) and MACS® (35). Here, PTPRC is linked to colorectal carcinoma.