MUC16-Mesothelin binding increases spheroid formation in ovarian tumor cells. The #7 and the #12 sublines were labeled with CellTracker Green. After keeping the cells in suspension for 1 h in peritoneal fluid, the homotypic doublet formation was measured by flow cytometry. The singlet events are shown in pink and the doublets are in green. The percentage of live cells that form the homotypic doublets is shown for each plot.