C5AR1 and metastatic malignant neoplasm in the lymph nodes: We found that a higher C5aR level was positively correlated with tumor size (OR = 1.58, 95%CI: 1.18–2.10, P = 0.002) and lymph node metastasis (OR = 1.99, 95%CI: 1.46–2.72, P<0.001) (Fig. S1).