NFKB1 and breast carcinoma: For example, NF-κB expression and activation is significantly increased in MCF7/LCC9 cells when compared to the parental, antiestrogen sensitive MCF7/LCC1 breast cancer cells; NF-κB can form functional heterodimers with IRF1 that regulate the expression of genes through an IFNγ activation site (GAS)/kappaB promoter element [84].