Interestingly, some genes, such as RAR-β2, are found methylated with similar frequencies in primary and metastatic CM, suggesting their methylation as being an early event in CM, while others have higher frequencies in advanced disease (e.g., MGMT, RASSF1A, DAPK), suggesting the implication of their aberrant hypermethylation in CM progression [39]. Here, RASSF1 is linked to cutaneous mastocytosis.