While we anticipated that KO of Klf4 specifically in AdvSca1-SM cells would alter their differentiation patterns during atherosclerosis progression, we also observed substantial shifts in the phenotype of YFP– non–AdvSca1-SM–derived cell populations in response to AdvSca1-SM cell Klf4 KO (Figure 6A). The gene discussed is KLF4; the disease is atherosclerosis.