Using two breast cancer cell lines, MCF-7 and MDA-MB 231, genistein influenced H3 and H4 histones on H3K27me3, H3K9me3, H3K4me3, H4K8ac, and H3K4ac marks, on six genes (EZH2, BRCA1, ERa, ERb, SRC3, and P300). The gene discussed is BRCA1; the disease is breast cancer.