ESR1 and breast carcinoma: The cholesterol metabolite 27‐hydroxycholesterol (27‐HC) stimulates ER‐dependent breast cancer proliferation by acting as the estrogen receptor ligand.[33] Additionally, the binding of 27‐HC to the liver X receptor facilitates metastatic processes in breast cancer murine models.[33, 34] Beyond these growth‐promoting effects, 27‐HC also maintains breast cancer stem cells, induces epithelial‐mesenchymal transition, and enables mammary tumorigenesis.[35] Together, these findings reveal broad pro‐oncogenic effects of cholesterol metabolism.