Further, SFN was found to improve sensitivity to DOX in breast cancer cell lines by inhibiting cell proliferation through the activation of Nrf2, HO-1, caspase, and anti-oxidant enzymes while repressing cyclooxygenase-2 (Cox-2), prostaglandin E2 (PGE2) and HDAC expression [78,79,81,85]. Here, HDAC9 is linked to breast cancer.