To identify new gene(s) that is potentially involved in the regulation of DNA de/methylation process (Figure 1A), we performed a comprehensive analysis of mutations targeting three families of genes which are known to be involved in DNA de/methylation; two IDH genes (IDH1 and IDH2), three TET genes (TET1, TET2, and TET3) and four DNMT genes (DNMT3A, DNMT3B, DNMT3L, and DNMT1) in 34 cancer types. Here, TET1 is linked to cancer.