In an in vitro study involving human pulmonary epithelial A549 cells, monkey COS-1 cells, and human breast cancer T47D cells, it was shown that GR-mediated inhibition of NF-κB activity occurs via a dual mechanism involving both protein-protein interaction between GR and NF-κB subunits and induction of IκBα expression; with the former mechanism being predominant in NF-κB regulation [244]. This evidence concerns the gene NR3C1 and breast cancer.