RASSF1 and nasopharyngeal carcinoma: In NPC, TSGs such as Ras association domain family member 1 (RASSF1A), cyclin-dependent kinase inhibitor 2A (CDKN2A), BLU, and deleted in lung and esophageal cancer protein 1 (DLEC1) which are involved in regulating the DNA repair and cell proliferation were silenced by promoter hypermethylation [25, 311, 312].