Ki-67 is widely used as a proliferation marker in cancer diagnosis,but little is known about its gene regulation.CpG methylation is a common epigenetic modification distributed at cis-regulatory regions and makes variable impacts on transcription.To determine whether DNA methylation is involved in Ki-67 gene regulation,we performed bisulfite sequencing and methylation specific PCR (MSP) to generate the methylation profile of Ki-67 promoter in vitro and in vivo,respectively.In normal and cancer cell lines with high expression of Ki-67 gene,we identified that Ki-67 promoter was hypomethylated.Besides,in clear cell renal cell carcinoma (ccRCC) specimens and matched normal renal tissues with different expression level of Ki-67 gene,an unmethylated profile of Ki-67 promoter was also observed.Our data indicated that methvlation status of Ki-67 promoter played little role in its gene regulation.