CLOCK and kidney cancer: As core clock genes promoter methylation can change the expression state of target genes, and CNV and SNV can change gene expression levels, exploring the changes in core clock genes structure, gene expression, and tumor pathogenesis by observing these indicators has certain clinical significance for the diagnosis and prognosis of kidney cancer (Diskin et al., 2009; Ricketts et al., 2012; Deng et al., 2017).