Röpke et al. [37] investigated the DNA methylation status of 8 tumor suppressor genes in a dedifferentiated CS case and found p16INK4A and E-cadherin promoter hypermethylation in both dedifferentiated CS sites, whereas methylation of the FHIT promoter was found only in the highly malignant dedifferentiated tumor component. Here, CDKN2A is linked to Cowden syndrome 1.