CST3 and aneurysm: Additionally, after review of evidence on cathepsins in atherosclerosis-based vascular disease, and feasibility studies of cathepsins as potential diagnostic tools, Cheng et al. (1) conclude that cathepsins S and L and endogenous inhibitor cystatin C could be used as biomarkers in determining the existence of coronary artery disease and the formation of aneurysms clinically.