The results showed that quercetin dramatically inhibited the binding of muliple transactivators (CREB-2, c-Fos, C/EBPβ, and NF-κB p50, NF-κB p65) to the COX-2 promoter probe in human breast cancer MDA-MB-231 cells (Figure 4B). This evidence concerns the gene NFKB1 and breast cancer.