Expression of CC chemokine receptor 5 in clear cell renal cell carcinoma and its clinical significance

DNA hypomethylation was the initial epigenetic abnormality recognized in human malignancy. In the present study, the GoldenGate high-throughput genotyping assay was adapted to determine the methylation state of 1,505 specific CpG sites in 807 cancer-related genes. The methylation results revealed that CC chemokine receptor 5 (CCR5) was hypomethylated (mean β-value difference, -0.21) in clear cell renal cell carcinoma (CCRCC) tissue. Tissue samples from 61 CCRCC cases were used for immunohistochemical staining, and patients with low CCR5 expression (n=44) were compared with those with high CCR5 expression (n=17). Tumor (T) stage was significantly lower in the low expression group compared with the high expression group (P=0.047). The Fuhrman grade of patients in the low expression group was significantly lower than that of patients in the high expression group (P=0.044). Whilst the node (N) and metastasis (M) stages of the CCR5 low expression group appeared to be lower compared with those of the CCR5 high expression group; this difference was not statistically significant (N stage, P=0.632; M stage, P=0.896). Additionally, patients in the low expression group had lower risks of postoperative tumor recurrence (P=0.110) and mortality from CCRCC (P=0.159) compared with those in the high expression group, however, this was also without statistical significance. The results indicate that CCR5 hypomethylation is associated with cancer tissue to a greater extent than normal tissue. Although the biological function of CCR5 in CCRCC remains to be established, low CCR5 expression is associated with low T stage and low Fuhrman grade in these patients.