Pathological significance of C3aR signaling in the tumor cells of clear cell renal cell carcinoma: a clinical observation

Abstract Background Increasing evidences suggest that anaphylotoxin-induced signaling is involved in tumor pathogenesis, but the exact role of C3a/C3aR signaling in clear cell renal cell carcinoma (ccRCC) still remains to be investigated. The aim of the study was to investigate the pathological significance of C3a/C3aR signaling in ccRCC. Methods The expression of C3aR and C3 mRNA in the tumor tissues of ccRCC patients were analyzed by using the data from TCGA database. The expression of C3aR and C3c protein in the tumor tissues of another 129 ccRCC patients were examined by immunohistochemistry. Results Compared with the normal controls, both C3aR and C3 mRNA increased in the tumor tissues. Patients with higher C3 mRNA had shorter survival time. Immunostaining for C3aR and C3c also increased in the tumor tissues when compared with the adjacent normal renal tissues. Higher level of C3aR in the tumor cells and C3c in the tumor tissues were found to be associated with indices reflecting poor prognosis including higher tumor grade, the presence of necrosis in tumor tissues and shorter survival time. Besides, the level of C3aR in the tumor cells and C3c in the tumor tissues were found to correlate with the level of Vimentin, E-Cadherin and the ratio of Ki-67 positive tumor cells. Conclusions These results support the idea that C3aR signaling is over-activated in the tumor cells and may contribute to the progression of ccRCC. Inducing EMT and promoting the proliferation of tumor cells might be among the mechanisms underlying the role of C3aR signaling in ccRCC.