Elevated levels of MMP-9 are independent predictors of unstable coronary plaque; in fact, virtual histology-intravascular ultrasound during coronary angiography in 32 patients with stable coronary disease found unstable coronary plaque properties, including increased necrotic core volume and fibro-fatty content, in patients with more elevated levels of MMP-9 (11). This evidence concerns the gene MMP9 and coronary artery disorder.