Abnormal methylation includes local hypermethylation of the promoter region in the CpG island of a specific gene and whole-genome hypomethylation in the genomic repeat regions [24] associated with malignant tumors [25,26], or the specific hypomethylation of some genes [24], such as signal-induced proliferation-associated protein 1 (SIPA1) [27]. Here, SIPA1 is linked to cancer.