5α,6α-epoxy Cholestanol is an oxysterol and a metabolite of cholesterol produced by oxidation.[1] 5α,6α-epoxy Cholestanol accumulates in MCF-7 breast cancer cells in a reactive oxygen species-dependent manner following tamoxifen and PBPE application and induces triacylglycerol biosynthesis by binding to liver x receptor β (LXRβ). [2] 5α,6α-epoxy Cholestanol levels are increased in rat aorta and mesenteric artery following orchidectomy, an effect that can be prevented by a DHA-supplemented diet.[1] Levels are also increased in post-mortem frontal and occipital cortex of patients with Alzheimer’s disease. [3]

Reference:
[1]. Villalpando, D.M., Rojas, M.M., García, H.S., et al. Dietary docosahexaenoic acid supplementation prevents the formation of cholesterol oxidation products in arteries from orchidectomized rats. PLoS One 12(10), e0185805 (2017).
[2]. Segala, G., de Medina, P., Iuliano, L., et al. 5,6-Epoxy-cholesterols contribute to the anticancer pharmacology of tamoxifen in breast cancer cells. Biochem. Pharmacol. 86(1), 175-189 (2013).
[3]. Testa, G., Staurenghi, E., Zerbinati, C., et al. Changes in brain oxysterols at different stages of Alzheimer’s disease: Their involvement in neuroinflammation. Redox Biol. 10, 24-33 (2016).