Extensive studies have reported that RARβ, CDH1, DAPK1, and GSTP1 genes are transcriptionally silenced not only through mutation and genomic instabilities (LOH, microsatellite instabilities, and homozygous deletions) but also by lack of expression due to promoter hypermethylation during the development of various human cancers [60–71]. This evidence concerns the gene DAPK1 and cancer.