DNA hypomethylation of interleukin 8 in clear cell renal cell carcinoma.

DNA hypomethylation is associated with carcinogenesis due to its involvement in cancer initiation and progression. In this study we analyzed the hypomethylation status of candidate genes in clear cell renal cell carcinoma (CCRCC) using a large-scale, high-throughput DNA methylation profiling technique. Results revealed that hypomethylated interleukin 8 (IL8) gene was the most prominent of the candidate genes, with a beta value difference of 0.406 (cancer tissue mean beta value, 0.346; normal tissue mean beta value, 0.752). Validation results using sequencing analysis demonstrated that the methylation rate was 2.4% in cancer tissue and 14.7% in normal tissue, whilst the non-methylation rate was 82.9% in cancer tissue and 52.9% in normal tissue. However, the hypomethylation status of IL8 had no significant relationship with Fuhrman's nuclear grade, tumor node metastasis (TNM) stage or survival (P>0.05). We revealed that the IL8 gene is maximally hypomethylated in cancer tissue compared to normal tissue.