HDAC1 and breast carcinoma: For example, in breast cancer cells, HDAC1–3 are inhibited by SFN to induce cell apoptosis [52, 53]; in skin cells, HDAC1–4 are regulated by SFN [34]; in the cochlea, SFN inhibits HDAC2, 4, and 5 [54]; and in colon cancer models, SFN downregulated only HDAC3 to prevent DNA damage repair [55].