BSG and ovarian cancer: Double-label immunofluorescence assays showed that CD147 protein labeled by green fluorescence and HE4 protein labeled by red fluorescence were observed in the cell membrane and cytoplasm of OVCAR3 and ES-2 cells (Figure 2B) and ovarian cancer tissues (Figure 3B), and the co-localization sites of CD147 and HE4 were observed by the overlapping orange fluorescence.