BCL3 and breast carcinoma: To confirm this result, we performed immunofluorescence staining and confocal microscopy of Bcl-3 localization in CACO-2, HCT-116, and breast cancer cell line MCF-7 and showed the accumulation of Bcl-3 in the cytoplasm of CACO-2 and HCT-116 but not in MCF-7 cells (Figure 5C).