A similar finding of the majority of foam cells being derived from SMCs was recently reported by the Ouimet group in mice injected with an adeno-associated viral (AAV) vector encoding gain-of-function PCSK9 (proprotein convertase subtilisin/kexin type 9) and fed a Western diet to induce hypercholesterolemia. Here, PCSK9 is linked to familial hypercholesterolemia.