Immunofluorescence staining showed more CD31 and Ki67 double staining positive cells in synovial tissues of patients with RA, respectively (108.6 ± 9.07 cells/mm3 and 401.4 ± 19.71 cells/mm3, p <0.01) (Figure 1C). The gene discussed is PECAM1; the disease is rheumatoid arthritis.