NFKB1 and breast cancer: In our present study, the limited expression of NF-κB p65 and IκBα in cytosol and the substantial expression of NF-κB p65 in the nucleus of mammary tumor cells from animals exposed to DMBA only indicate the conceivable degradation of IκBα, release of activated NF-κB p65, and its subsequent translocation to the nucleus.