NKX6-2 and renal cell carcinoma: Thus, both our biometrical analysis identifying candidate CpG loci in three regions of NKX6-2 as being among the top 30 candidates for association with RCC metastasis, and the detection of frequent hypermethylation in tumor cell models representing frequent human tumor entities, are in line with previously published data and point to a broader relevance of alterations in NKX6-2 methylation.