Plasma and urine SFN metabolites, PBMC HDAC activity, and tissue biomarkers, such as HDAC3, HDAC6, H3K18ac, H3K9ac, Ki-67, and p21, were measured pre- and post-treatment in benign, ductal carcinoma in situ (DCIS) or invasive ductal carcinoma (IDC) breast tissues. The gene discussed is HDAC9; the disease is ductal breast carcinoma in situ.