Marc Poirot is first class research director (DR1) at the Institut National de la Santé et de la Recherche Médicale (INSERM). He heads the team ‘Cholesterol metabolism and therapeutic innovations’ at the Cancer Research Center of Toulouse. He received a PhD in Chemical Biology (1991) from the University of Toulouse. He did a postdoc at Sanofi before becoming tenured at INSERM in 1992. He was visiting scientist from 1993 to 1996 in the laboratory of Dr S. S. Simons Jr (NIDDK/NIH, Bethesda, USA) to study steroid hormone receptors. Since then, his research has focused on the pharmacology of the antiestrogen tamoxifen and on cholesterol metabolism deregulations in breast cancers. He, with his team, discovered the existence of a new metabolic branch on the cholesterol pathway involved in breast oncogenesis. This branch is centered on cholesterol-5,6-epoxide whis is transformed into a tumor suppressor metabolite named dendrogenin A (DDA) after conjugation with histamine or metabolized into an oncometabolite with tumor promoter properties named oncosterone (OCDO) in tumors. He trained tens of postgraduate students, filed a dozen of patent applications, published numerous SCI journal papers, edited/reviewed for many academic journals, served as an evaluation expert for organizations such as the French National Research Agency.