Because correlation analysis using wild-type C57BL6/J mice and PCSK9−/− knockout mice showed that higher PCSK9 expression indicated worse cardiac function after acute myocardial infarction and that PCSK9 knockout improved cardiac function and reduced infarct size along with attenuated inflammation in this tissue [35], the heart was selected for molecular analysis in our study. The gene discussed is PCSK9; the disease is myocardial infarction.