Secreted frizzled related proteins (SFRP1, SFRP2, SFRP3), which are Frizzled competitors for Wnt, are silenced by promoter hypermethylation in different cancers, including hepatocellular carcinoma (HCC), lung adenocarcinoma, oesophageal squamous cell carcinoma (ESCC) and CRC [49–52]. This evidence concerns the gene SFRP1 and hepatocellular carcinoma.