SFRP2 and nasopharyngeal carcinoma: Furthermore, we found that Wnt5B, SFRP1, and SFRP2 were hypermethylated in nasopharyngeal carcinoma tissues (Additional file 3: Figure S3), and the hypermethylation of DKKs and DACTs in nasopharyngeal carcinoma tissues was also confirmed [15, 36].