Among them, DNA promoter CpG island hypermethylation was the most frequently reported mechanism in NPC (38, 39), such as RASSF1A, RASSF2A, CDKN2A, ADAMTS18 (5, 40–43), which contributed to the early pathogenesis, even earlier than EBV infection (38, 44). The gene discussed is RASSF1; the disease is Epstein-Barr virus infection.