SFRP1 and oropharynx cancer: In this regard, frequent hypermethylation of the negative regulators of this pathway (DKK-3, RUNX3, SFRP1, SFRP2, SFRP4, SFRP5, and WIF1) was observed in oral and oropharyngeal cancers [7, 10, 11, 26–28].