We confirmed that IL18 is highly expressed in RCC tumor, and high IL18 expression is associated with different pathological stages and poor prognosis in RCC patients (Fig. 1A–F) Then, we identified six significantly differentially methylated CpG sites: cg04100971, cg04929355, cg05687149 cg09122223, cg11304234 and cg26534425, most of which were significantly hypomethylated in tumor tissues except cg04100971 (Fig. 2A–C). This evidence concerns the gene IL18 and renal cell carcinoma.