Flow cytometry analysis of SSEA-4 in NCCIT (red filled histogram) and HeLa cells (red unfilled histogram) compared to unstained cells (blue histogram). Positive staining is observed on NCCIT cells when compared to no antibody control (middle panel) and to SSEA-4-negative HeLa cells (right panel). Cells were fixed with 2% paraformaldehyde and washed with PBS. Cells were blocked with 2% BSA-PBS for 30 minutes at room temperature and incubated with a PE-conjugated SSEA-4 monoclonal antibody (Product # MA1-021-PE) in 2% BSA-PBS at a dilution of 1:100 for 60 minutes at room temperature. Cells were washed and re-suspended in PBS for FACS analysis.