Fig. 2

Recovery of tumor cell line cells in cryopreserved peripheral blood mononuclear cells (PBMCs) samples. Healthy blood samples were spiked with three tumor cell lines: MCF-7 (a), PC-3 (b), and 786-O (c). The PBMCs and tumor cells were isolated with Ficoll separation and then cryopreserved. The tumor cells were retrieved after thawing through CellSieve™ microfiltration. Day 0 (fresh) was a control sample without cryopreservation. Day 7 and day 66 (frozen) were the samples after cryopreservation. Each biomarker expression is indicated as CK8, 18, 19/FITC (green), EpCAM/PE (orange), vimentin/EF615 (red), and CD45/Cyanine5 (magenta). a The MCF-7 and PC-3 cells were stained as a pattern of CK+/EpCAM+/CD45−. b White blood cells (WBCs) were stained as CK−/EpCAM−/CD45+. c The 786-O cells were stained as CK+/vimentin+/CD45−, whereas WBCs were stained as CK−/vimentin ±/CD45+ because of cross-reactivity of vimentin antibody. The morphologic characteristics and antibody staining patterns of the tumor cells were unchanged after cryopreservation for 66 days