Hence,considering the pathological role of HDAC3 in triple-negative breastcancer (TNBC), the antitumor properties of compound 21 were investigated in this cell line, and a 40-fold selective antiproliferativeeffect toward breast cancer cells over healthy cell lines, such ashuman breast cells (MCF-10A), human embryonic kidney-293 (HEK-293),and human corneal epithelial cells (HCECs), was observed. This evidence concerns the gene HDAC3 and breast carcinoma.