C5AR1 and neoplasm: Besides, a higher level of C5aR expression was associated with larger tumor size (OR = 1.58, 95% CI: 1.18–2.10, P = 0.002) and the occurrence of metastases in lymph nodes (OR = 1.99, 95% CI: 1.46–2.72, P<0.001), whereas it was independent of tumor stage, vascular invasion and tumor differentiation.