SFRP1 and neoplasm: We also discovered several genes from the Wnt pathway with hypermethylation in EBVaGCs relative to LDs/normal tissues, including DKK3 (P = 0.0022), SFRP1 (P = 0.0034), and SFRP2 (P = 0.0005) (Additional file 1: Figure S8c), and these genes have been reported to be frequently methylated and to function as tumor suppressors in NPCs [41].