MKI67 and atherosclerosis: We also identified lesion‐resident proliferating cells as macrophages in human coronary arteries using Ki67 and CD68 immunostaining (Figure 3, upper panel).9, 23 Immunofluorescent staining showed that Ki67‐positive cells are also CD68 positive (Figure 3A through 3D), thus identifying locally proliferating macrophages in human atherosclerosis, consistent with findings by Robbins et al.9 Furthermore, IHC of macrophage‐rich areas of human lesions illustrated the presence of Ki67‐positive cells (Figure 3E through 3G).