CX3CL1 and nonpapillary renal cell carcinoma: The results showed significant differences in CX3CL1 expression among different subgroups of histologic grade (P <  0.001), T stage (P <  0.001), M stage (P <  0.05), and pathological stage (P <  0.001), suggesting that the higher the expression level of CX3CL1, the lower is the tumor malignancy in ccRCC patients (Fig. 2E–H).