In addition, we observed a number of CES‐R/M‐specific mutations in epigenetic regulators such as ARID1A, ARID1B, CTCF, KMT2C, KMT2D, PBRM1, and SETBP1, suggesting that metastatic progression of CES may be associated with loss of epigenetic regulation. This evidence concerns the gene KMT2C and cat-eye syndrome.