DKK1 and malignant colon neoplasm: Many of the genes, which showed the age-related expression and methylation changes in our study associate with Wnt/β-catenin signaling, although, their changes did not necessarily imply Wnt signaling activation as does the expression decrease of Dkk1 and Sfrp1. The Wnt/β-catenin signaling pathway is aberrantly activated in most human colon cancers [27,28].