CD34 and aortic aneurysm: In Carmen's review, SCA1 + CD34 + VSMCs were defined as mesenchymal cell-like VSMCs [21], which included the "SEM" cells in Pan et al. The two most significant terms identified by GO enrichment analysis of "SEM" cells were "Extracellular matrix organization" and "Extracellular structure organization," which is consistent with our GO analysis results of mesenchymal-like VSMCs in aortic aneurysms.