Bao et al.38reported that many complement genes such as C3, C4R, C5aR1 were overexpressed in gastric and colon cancer compared with normal tissues. Mangogna et al.39reported that C1q was overexpressed in breast cancer and kidney cancer, while in lung cancer, a lower level of C1q expression was found. We suspected the low mRNA expressions of complement genes in HCC might result from the fact that liver is an organ with predominant innate immunity full of complement proteins.40 Here, C5AR1 is linked to kidney cancer.