Fig. 3

Sialyl-glycolipid stage-specific embryonic antigen 4 (SSEA4) expression is found in metastatic cells that survived genotoxic chemotherapy. a The surface expression of SSEA4 on primary cells from patient-matched xenografts (passages 1–3) was evaluated. Each xenograft was stained with an isotype control (gray histogram) or with an SSEA4 antibody (blue histogram). b Quantification of SSEA4 expression on the cell surface of six xenografts obtained from metastatic pleural effusions (PE) or circulating tumor cells (CTCs) from M1-stage metastatic breast cancer patients. The median fluorescence intensity (MFI) ratio is calculated as the MFI of SSEA4-stained cells divided by the MFI of the isotype control-stained cells. c Schematic overview of each metastatic breast cancer patient’s treatment characteristics. CT chemotherapy)